1985 Checklist of Vascular Plants of the Anza-Borrego Desert
Revised by Tom Chester, 2006
The Floristic Areas
Numerology of the Checklist
Rejected Taxa That Do Not Occur In San Diego County
Rejected Taxa That Occur In San Diego County, But Not In The Desert
Taxa Without Vouchers In The Original Checklist That Now Have Vouchers
Taxa Approaching the Area
Number of Taxa by Floristic Area
Introduction and Summary
Duffie Clemons compiled a checklist of Vascular Plants of the Anza-Borrego Desert State Park in 1985, for the San Diego Chapter of the California Native Plant Society and for the Anza-Borrego Desert Natural History Association. As far as I know, this was the first checklist produced for the desert portion of San Diego County, and is still an important and useful checklist.
The Clemons Checklist has the following significant features:
- It is highly complete, since Clemons used multiple sources to compile it. In addition to informal checklists compiled by Clemons and others from fieldwork, Clemons went through the entire collection of the San Diego Natural History Museum (SDNHM) Herbarium, and added every taxon that was collected in the desert region of San Diego County.
Of course, higher completeness usually means lower reliability. About 10% of the taxa in the original published Checklist aren't actually present in the desert. Those taxa have been removed in the update given here.
- The Checklist splits the desert region of San Diego County into four floristic areas, and separately indicates which taxa are found in each of those areas. Thus it gives at least limited information about the geographic distribution for each taxa.
- The Checklist indicates which taxa are supported by vouchers, and which taxa are not (it includes both categories). In the update here, taxa that do not have at least one voucher in the desert are deleted. But as long as one voucher exists in one floristic area, unvouchered reports for other floristic areas are retained.
- The Checklist is not exactly synonymous with a Checklist for the Anza-Borrego Desert State Park area; the boundaries are drawn differently. See The Floristic Areas for details.
This Checklist is a portion of a much larger work by Clemons, checklists for each of the 26 floristic areas of San Diego County defined by Frank Gander. These checklists provide a snapshot of what the flora of San Diego County was like in 1985. This is especially significant in light of the continued destruction of habitat by "development" and urbanization, as well as by the continued onslaught of non-native species.
Much work on the flora of the Anza-Borrego Desert has been done since 1985; notable sources relevant here are:
- Beauchamp produced his Flora of San Diego County in 1986, a huge piece of work that was a true flora of the entire County, including the roughly one-third represented by the desert portion. Beauchamp's Flora had keys and information on the frequency, habitat, and locations for each taxon, along with flowering times.
Beauchamp's highly-portable, authoritative book quickly became the standard reference for San Diego County, including in the field, relegating the Clemons Checklist to more of an academic role in seeing in a single checklist what species had been found in the desert.
- Simpson et al began producing updated checklists for San Diego County as a whole in 1995, with updates in 1996 and 2001 and a soon-to-be-released update by Rebman and Simpson in 2006. As a result of their important detailed work, San Diego County is the only place in Southern California with a checklist kept up to date over a long time period.
- The Jepson Manual of 1993 provided a new standard reference for California plants, with updated botanical knowledge that included the addition of a number of newly-defined taxa, the subtraction of a number of taxa that were found not to be truly-distinct taxa, as well as a number of new scientific names.
- Many botanists have continued to do fieldwork in the desert, and many additional vouchers are now available. In particular, the San Diego County Plant Atlas project began in 2003, and has produced a significant increase in knowledge about the flora of San Diego County.
- Most herbaria have now digitized all or many of their vouchers, and make them easily available online. In particular, the Consortium of California Herbaria has the full information on over 700,000 vouchers online. This creates a rich resource that can easily be tapped to verify species in the Clemons Checklist, and also to add new species to it.
- Wayne Armstrong, with contributions from Tom Chester, has also compiled a valuable checklist for the Park that is the result of independent fieldwork, and contains additional taxa beyond that in the Clemons Checklist.
The update presented here of the Clemons Checklist incorporates much, but not all, of the above as a first step toward producing a new updated Checklist. The Checklist given below is an update of the 1985 Checklist to the names used in the 1986 Jepson Manual, and includes only taxa with vouchers, rejecting all other taxa. For taxa without vouchers reported by Clemons, I have used the above sources to search for vouchers not known to Clemons when he compiled his Checklist.
No new taxa have been added to the 1985 Checklist except for ones given in previous Clemons checklists of the individual floristic areas that he inadvertently omitted from the 1985 Checklist. I have only deleted taxa that are not supported by vouchers. The rejected taxa are given in separate lists below.
Thus this updated Clemons Checklist should more accurately reflect the taxa known to be present in the Anza-Borrego desert as of 1985, in terms of the 1996 knowledge of taxa given in the Jepson Manual. A subsequent version will update the Checklist to 2006 by incorporating new vouchered additions from sources listed above. This page will then primarily be a reference for that 2006 updated Checklist, as well as a historical checklist.
Specifically, the changes made here are the following:
- There were 18 taxa given by Clemons in his separate checklists for one of the individual Floristic Areas, many of which were apparently-inadvertently omitted from the Clemons Anza-Borrego Checklist; these were added back to the Checklist;
- All taxa have been updated to the ones used in the Jepson Manual, which removed about 10% of the listed taxa as being synonymous with other listed taxa;
- All taxa not present in the 2001 Simpson and Rebman San Diego County Checklist are deleted, except for those added by the San Diego County Plant Atlas that will be present in the 2006 San Diego County Checklist and one vouchered taxon that will likely be added in a future update of the San Diego County Checklist. This deleted about 4% of the taxa with updated names;
- Taxa that were just reported by Clemons, without a voucher found by Clemons in the SDNHM Herbarium for at least one of the Floristic Areas comprising the Checklist, were deleted if an online voucher could not be found to support them. This deleted about 7% of the taxa with updated names.
The updated checklist presented here contains 835 taxa. The detailed numbers that give the changes due to each step of the above are given in the Numerology of the Checklist below.
In addition, I give a list of 13 taxa that are found in nearby areas but have not yet been found in the San Diego County portion of the desert. Most, but not all, of these taxa were ones deleted from the Checklist.
It unfortunately was not possible to do one important verification of the Clemons work, despite significant attempts to do so. I would have liked to:
- verify the SDNHM vouchers reported by Clemons, and associate a specimen number with each record of a taxon in each Floristic Area, and
- check for omissions of taxa and omissions of records for individual floristic areas.
Also, as a result of the lack of this file, I had to use Beauchamp as a proxy for the existence of vouchers for some taxa (see below).
Although these SDNHM vouchers are not yet online anywhere, they apparently were digitized by California State Parks sometime around the year 2000.
I have made repeated attempts to obtain a copy of this file by email and phone calls to the staff of the Anza-Borrego Desert State Park and the SDNHM Herbarium over nearly a full year from 24 March 2005 to 6 March 2006. Unfortunately, as of 12 March 2006 I still have not received a copy of that file. Since it seems likely that taxpayer dollars were used to digitize that file, the lack of response to my attempts seems quite puzzling. Science is not served by keeping valuable data locked up.
The Floristic Areas
Whoever conceived of organizing San Diego County into Floristic Areas, and producing checklists for each one, had an excellent idea. These checklists contain a wealth of data on the plant distribution in San Diego County that has yet to be mined. One of my motivations in updating each of these checklists is to analyze these data.
The history of the Floristic Areas of San Diego County is a bit hazy, since few dates are associated with its products. The one known date is 1949, when Ethyl Higgins produced a checklist for all of San Diego County. The other products are probably coeval with that checklist.
The Floristic Areas were apparently defined by Frank Gander, who produced a map on a single 8.5 x 11 inch piece of paper showing boundaries of the 26 Areas. Ethyl Higgins and Margaret Lyall produced 3-4 page checklists for each of the areas.
In 1983-1985, Duffie Clemons produced updated checklists for all of the Floristic Areas. In 1985, he updated and combined four of those checklists to produce his Anza-Borrego Checklist.
The Floristic Areas in eastern San Diego County are shown below as the areas bounded in purple and by the San Diego County Border, shown as a dashed blue line, with its number near the center of each area:
The Anza-Borrego Checklist is made from Areas 7, 8, 9 and 16. The union of those areas is not exactly the same as the area of Anza-Borrego Desert State Park, shown in red in the above map. In particular, note that the Park includes nearly half of Floristic Area 26, the San Ysidro Mountains, not included in the Checklist; and ~half of Floristic Areas 7 and 9 in the Checklist are not contained in the Park. The map above also shows Floristic Area 17, the Lake Henshaw basin.
Thus the Clemons Checklist should more properly be called the name I have given it here, Checklist of Vascular Plants of the Anza-Borrego Desert, rather than the name Clemons gave it, Vascular Plants of the Anza-Borrego Desert State Park.
The definition used by Clemons for his Checklist is actually more useful to botanists visiting the desert portion of the Park, since it doesn't include the montane species present in a checklist for the Park. (It is a bit incongruous driving along the crest of the Laguna Mountains on the Sunrise Highway and come across a boundary marker for Anza-Borrego Desert State Park!) Adding the montane species would significantly increase the number of species on the Checklist, which would just add noise in using the Checklist to try to determine the identifications for species on the desert floor.
A brief description of each area in the Checklist follows:
- Area 7 is the extreme southeast portion of San Diego County, including Jacumba, Mountain Spring, Boulevard, Carrizo Gorge, Dos Cabezas and most, but not all, of the Jacumba Mountains.
It is roughly a square with sides of 12 miles, an area of ~150 square miles. Elevations are 1200-4647 feet (366-1416 m), with a median elevation of around 3000 feet (900 m).
- Area 8 is immediately north of Area 7, and is dominated by the Vallecito Creek Drainage. It also includes highland areas in the Jacumba, Vallecito, and Tierra Blanca Mountains.
It is roughly a rectangle with sides of 20 miles north-south and 13 miles east-west, an area of ~250 square miles. Elevations are 440-5349 feet (134-1630 m), with a median elevation of around 1500 feet (500 m).
- Area 16 is the extreme northeast portion of San Diego County, and is mostly the Borrego Valley Area, including Clark Valley, the portion of the Santa Rosa Mountains in San Diego County, and the northern portion of the Vallecito Mountains.
It is roughly a trapezoid with parallel east-west sides of length 25 miles at the north end and 16 miles at the south end, and non-parallel other sides of length 27 and 29 miles, an area of ~550 miles. Elevations are 100-6040 feet (30-1840 m), with a median elevation of around 1000 feet (300 m).
- Area 9 is the desert foothills, the eastern slope of the Laguna Mountains. It includes the Montezuma, Culp, San Felipe, Blair, Mason and McCain Valleys; Granite Mountain, the west side of the Pinyon Mountains, the San Felipe Hills, and Pinyon and Yaqui Ridges.
Its shape cannot be described by a simple geometric shape; its dimensions are roughly 37 miles by 4-14 miles, an area of ~300 square miles. Elevations are 1125-4573 feet (342-1394 m), with a median elevation around 3000 feet (900 m).
Unfortunately, the precise locations of the boundaries are not defined, and some of the boundaries are somewhat arbitrary. The most natural boundary is the one on the desert slopes of the Laguna Mountains, but the precise location, especially the precise elevation, at which to place the boundary is arbitrary and not specified as far as I know.
Hirshberg took the boundary to be the 3000 foot elevation contour for the Cuyamaca and Laguna Mountain Checklist she produced with Clemons. The 3000 foot contour is pretty close to the line drawn by Gander north of Mt. Laguna. South of Mt. Laguna the mean boundary of Gander's line around the Laguna Mountains is roughly 5000 feet due to the high In-Koh-Pah Mountains to the southeast.
Most of the other boundaries appear to define drainage basins, which is as good a way to do it as any.
The boundary between the San Ysidro Mountains and the Borrego Valley is also roughly at 3000 feet in its northern half, but drops to a surprising value of 1000 feet below that. As a result, everything above the lowest falls in Borrego Palm Canyon is in the San Ysidro Mountains Area, as is the entire last half of the Trail from the Parking Area to Maidenhair Falls in Hellhole Canyon!
But floristic boundaries have to be drawn somewhere in order to produce a flora, and there is never an excellent place to draw a boundary except along a coastline or a similar well-defined barrier.
Numerology of the Checklist
The numbers presented here are given in a compact table at the end of this section, which might be a clearer way for some readers to follow this discussion. A glance at that table now is recommended as an overview of the following.
There are 1,052 entries in the printed Clemons Checklist with distributional information. Another 18 taxa, including vouchered taxa well-known to appear in the desert such as Gutierrezia sarothrae and Phacelia campanularia ssp. campanularia, were found in one of the individual Area Checklists, but were omitted from the final Checklist. Adding these taxa produced a total of 1,070 taxa.
Of those 1,070 taxa, 125 taxa are synonymous with another entry, using the taxa as given in the Jepson Manual, leaving 945 Jepsonized taxa. (See below for comments on what were considered synonyms.)
An additional 40 taxa were deleted because they were not in the 2001 San Diego County Checklist by Simpson and Rebman, and were not listed as a Rebman-confirmed vouchered taxon in the San Diego County Plant Atlas. These are usually misidentifications, and often are ones that are not found anywhere near this area. This left 905 taxa.
One taxon, Lemna aequinoctialis, was not deleted even though it fit the criteria here because it has a voucher in Germany that was apparently overlooked for the San Diego County Checklist.
The synonymous taxa here include true synonyms, as well as "Clemons" synonyms that are technically misidentifications. An example of the latter is as follows.
Clemons gives Gilia achillaefolia ssp. achillaefolia as well as G. capitata ssp. abrotanifolia in his original Checklist. These are two different taxa, and are not synonymous. Yet in some of the individual Area lists, such as Area 9, he gives only G. achillaefolia ssp. achillaefolia, even though he reported G. capitata as being in Area 9 in the Checklist.
These two species are quite close, being separated by a fairly subjective trait (are the heads spheric or gen hemispheric?) and some gen traits, and thus it would be easy to misidentify an individual specimen. However, it is generally agreed that these two taxa are indeed distinct species and separate on location.
Because G. achillaefolia is considered to only be present well north of Southern California, taxa in San Diego County so identified are clearly G. capitata. Since it is therefore obvious that Clemons was describing plants corresponding to G. capitata whenever he mentioned G. achillaefolia, I've treated this as a "Clemons synonym", and assigned the distributional information given by Clemons for G. achillaefolia to G. capitata.
In other cases, it is not possible to determine the true identity of a taxon when, for example, Clemons gives a taxon name found only in DMoj that is not extremely close to a taxon found in San Diego County. Those taxa were treated as misidentifications and the information totally discarded. Most of these were only taxa reported in the Checklist, without vouchers. Not much actual information was discarded in this process, since many of these taxa were also in the Checklist under their correct name, as in the example above.
All remaining taxa that were not listed by Clemons as being vouchered in at least one Area by a specimen at the SDNHM Herbarium were then examined to see if a voucher for one of the Areas could be found, using the following procedure.
Procedure for searching for vouchers: The first check for a voucher was to search the Consortium of California Herbaria Database. If one was found, the specimen number was recorded, and is given in a table below.
If a voucher was not found, the San Diego County Plant Atlas was searched for a voucher. If one was found, the data collection number was recorded, as well as whether Rebman had confirmed the voucher. (Unfortunately, the SDNHM Herbarium acquisition number is not given online, so I had to settle for recording the Plant Atlas identification number.)
Finally, if no voucher was present in the Plant Atlas, Beauchamp was consulted to see if he reported that taxa in one of the Areas. If so, that information was recorded and the taxon was kept in the Checklist, since this possibly meant that Clemons had simply overlooked a voucher present at the SDNHM Herbarium. If I ever get the voucher file from the SDNHM Herbarium, it will be simple to search for any such voucher.
In the procedure above, the Consortium of California Herbaria Database was searched first because it provides complete voucher information. This enabled a more accurate determination of whether a given voucher was actually in one of the Areas, and not in a nearby Area.
Unfortunately, the San Diego County Plant Atlas does not provide complete voucher information such as a detailed location or an elevation. A number of grid cells in the San Diego County Plant Atlas are split between one of the Areas in this flora and one of the neighboring Areas not in this flora. Without elevation and / or detailed location information it is not possible to resolve this ambiguity. Therefore a small number of taxa not actually found in an Area here are possibly retained here instead of being rejected.
In January, I asked the San Diego County Plant Atlas for access to that data. If and when I receive it, I will examine all ambiguous vouchers.
It is also easier to search the Consortium Database since one only has to enter a scientific name as a whole to search it, whereas the Plant Atlas requires separation of the genus and species (actually the specific epithet for jargon-lovers), as well as checking two boxes.
A total of 69 taxa were rejected as not having any supporting voucher or indication that a voucher might be present, leaving a total of 838 taxa. The number was further reduced by one by combining the Ferocactus cylindraceus varieties, as was done in the Flora of North America treatment which will be followed in the 2006 San Diego County Checklist. This leaves a total of 835 taxa in the final Checklist given below.
There are possibly only 834 distinct taxa in the final Checklist, since the species Descurainia pinnata is retained as an entry, along with two of its subspecies, because Clemons gave additional Areas for the species that were not assigned to a subspecies. When those species vouchers are determined to the subspecies level, it may result in a third subspecies being in the flora, in which case there would indeed be 835 distinct taxa in the Checklist. It may also be the case that these vouchers are determined to be one of the previously-given two subspecies, in which case there would be 834 distinct taxa in the Checklist.
The following table summarizes the information present above:
# taxa in original Clemons Checklist 1,052 # taxa omitted from original Clemons Checklist 18 # taxa in corrected original Clemons Checklist 1,070 Removed Taxa # synonyms 125 # taxa not in San Diego County 40 # taxa without supporting vouchers or mention in Beauchamp 69 Eliminate Ferocactus cylindraceus varieties 1 Total taxa removed 235 # taxa in updated Clemons Checklist 835
The following sections detail the changes summarized above.
It is interesting to note that the original Clemons Checklist, after synonyms and taxa not in San Diego County were removed, contained ~17% more taxa than the list obtained from the union of his individual Checklists for Areas 7, 8, 9 and 16. There is no mention in the Checklist of this increase. I speculate that the increase may have been due to feedback from a preliminary Desert Checklist he put together in 1984, and/or from checklists for specific areas he learned about after doing the individual Area Checklists.
The following 18 taxa were found in one of the individual Area Checklists, but were not present in the final Checklist. Since some of these are vouchered taxa well-known to appear in the desert such as Gutierrezia sarothrae and Phacelia campanularia ssp. campanularia, it appears that many of these were simply apparently-inadvertently omitted from the final Checklist. Thus I have added all of these to the Checklist.
Six of these 18 taxa were later found to have no vouchers and so were subsequently deleted from the final checklist, and are so marked in the table. This deletion rate is significantly higher than the overall 10% deletion rate of taxa in the entire Checklist, indicating that some of these were perhaps intentionally deleted by Clemons.
Family Scientific Name Subsequently Deleted By Lack of Voucher Asteraceae Gutierrezia sarothrae Asteraceae Lactuca serriola Asteraceae Stylocline gnaphaloides Fabaceae Lotus scoparius var. scoparius Hydrophyllaceae Phacelia campanularia ssp. campanularia Onagraceae Camissonia hirtella Polygonaceae Nemacaulis denudata var. gracilis Scrophulariaceae Penstemon Xparishii (P. centranthifolius X P. spectabilis var. spectabilis) Solanaceae Physalis hederifolia var. fendleri Cyperaceae Cyperus laevigatus Juncaceae Juncus bufonius var. bufonius Liliaceae Chlorogalum parviflorum Fabaceae Astragalus lentiginosus var. coachellae x Hydrophyllaceae Phacelia imbricata ssp. patula x Polygonaceae Eriogonum wrightii var. trachygonum x Ranunculaceae Ranunculus canus x Juncaceae Juncus rugulosus x Poaceae Vulpia microstachys var. ciliata x
I've updated a large number of checklists, but updating this Checklist was more difficult than any other I have done. An almost bewildering variety of names was used in the original Checklist, a number of which I had never before encountered in a Southern California checklist. (A number of names were of taxa only found in the Mojave Desert (DMoj), and I have not yet digitized any DMoj floras.)
The large number of names undoubtedly reflects both the lists Clemons used, made by a number of different people with a range in ability to correctly identify a specimen, as well as the state of the SDNHM Herbarium in 1983-1985. Many vouchers Clemons found probably still had the original names assigned many decades ago.
The synonymous taxa here include true synonyms, as well as "Clemons" synonyms, as discussed earlier for Gilia achillaefolia.
In particular, note that some of the following Clemons Synonyms are not actual synonyms in the sense that these are identical taxa! Instead, some of these are names used in a Clemons checklist for which I am reasonably certain that they have been misapplied to a taxon in San Diego County and I am reasonably certain of the proper name for that taxon. The following example may also help to clarify this distinction.
The record number of synonyms in the Checklist belongs to the taxon now known as Quercus cornelius-mulleri. This taxon was published in 1981. Since it typically takes years to decades for most botanists to become aware of such changes, it is understandable that a 1983-1985 Checklist might show earlier names as well.
Prior to 1981, the Anza-Borrego Desert scrub oaks had been first lumped with cismontane scrub oaks into Q. dumosa. Then, at about the same time in ~1982, the scarce coastal plants were separated out and were then the only ones to get the name Q. dumosa, with the vast majority of the cismontane scrub oaks now under the name Q. berberidifolia. Also prior to 1981, some authors lumped the Anza-Borrego Desert scrub oaks into one or the other subspecies of Quercus turbinella, taxa found in DMtns far to the east.
As a result of these changes, this single taxon of Q. cornelius-mulleri was listed under four different names in the original Checklist, and a fifth different name in some of the checklists for the desert Floristic Areas.
A number of other taxa were listed in the original Checklist under three different names, which were different varieties or subspecies that were subsequently combined in Munz or the Jepson Manual.
Due to the large number of synonyms used by Clemons, they are presented on a separate webpage.
Rejected Taxa That Do Not Occur In San Diego County
There are 40 taxa that do not appear in the 2001 San Diego County Checklist, and which do not have a confirmed voucher from the San Diego County Plant Atlas.
The following table gives the Jepson Manual Scientific Name, the name used by Clemons, the Jepson Manual rarity and distribution information, and whether Clemons stated that there was a voucher for that taxon, with the number of the floristic areas that had vouchers (AB means a voucher was at the herbarium in the Anza-Borrego Desert State Park). If there is no entry in the column labeled Clemons voucher in Area x, it means that Clemons only had a report of that voucher in the Checklist. For taxa with a distribution in the Jepson Manual that might include San Diego County, the Munz distribution, which is usually more detailed, is given. Comments are given when appropriate.
Five of the taxa are in surrounding counties very close to San Diego County, and it is possible that vouchers within San Diego County might be found for some of these in the future. (These taxa are also listed in a separate table below for that reason.) It is also possible that reports of these taxa resulted from observations close to the county line where the reporter was unaware that they were just outside the San Diego County border.
Many of these taxa are undoubtedly misidentifications from observations in the field, and possibly made by observers who were unaware how close some taxa are. For example, the Jepson Manual states that Berberis haematocarpa is perhaps best treated as part of B. fremontii, so these taxa are clearly very close. B. fremontii is in the vouchered Checklist.
Some of the reported species probably came from older vouchers in the SDNHM Herbarium that had not been redetermined for some time. In the course of updating the names, I came across an almost-bewildering zoo of names, a number of which I had never seen before, despite updating dozens of old checklists. Clemons was simply reporting names he saw in the SDNHM collection, and clearly made no significant attempt to update any reported names, as the example of Gilia achillaefolia above shows.
Family Scientific Name Clemons Name (if different) JM distribution in Southern California Munz distribution Comments Clemons voucher in Area x JM family Latin Name Duffie Name JM distribution in Southern California Munz distribution Comments Duffie voucher in Area x Amaranthaceae Amaranthus watsonii very uncommon; s DSon (Imperial County) 9 Apiaceae Ammoselinum giganteum RARE in CA; DSon (Hayfield Lake, Riverside Co., 1922) AB Asteraceae Baileya juncea -- No taxon exists with this name; could this be Bebbia juncea?? Asteraceae Coreopsis bigelovii Coreopsis bigelovii TR, Teh, DMoj, n DSon San Gorgonio Pass to Death V. 9 Asteraceae Coreopsis douglasii n WTR Asteraceae Pyrrocoma uniflora var. gossypina Haplopappus uniflorus ssp. gossypinus RARE; SnBr (near Baldwin Lake) Berberidaceae Berberis haematocarpa e&s DMoj; "perhaps best treated as part of B. fremontii (in PR)" Boraginaceae Cryptantha recurvata DMoj Boraginaceae Pectocarya anisocarpa -- Unpublished name; disposition unclear 9, 16 Brassicaceae Arabis hoffmannii RARE; n ChI (Santa Cruz Island) Cactaceae Echinocereus triglochidiatus D Inyo-White Mtns to mts. of Riverside County Cactaceae Opuntia wigginsii -- Probably not a valid taxon, just a depauperate form of Cylindropuntia echinocarpa; see Chollas of Southern California Capparaceae Cleomella plocasperma Cleomella plocasperma var. mojavensis DMoj Euphorbiaceae Chamaesyce parishii Euphorbia parishii uncommon, D infrequent, both deserts from Death V. to e. San Diego County closest voucher is near Palm Wash on eastern flank of Santa Rosa Mountains Euphorbiaceae Chamaesyce platysperma Euphorbia platysperma DSon (Coachella Valley); not seen in CA since 1914 Fabaceae Astragalus lentiginosus var. coachellae Astragalus lentiginosus var. coachellae DSon (Coachella Valley) Fabaceae Lathyrus vestitus var. vestitus Lathyrus laetiflorus ssp. laetiflorus SW Santa Monica Mts. to San Jacinto and Santa Rosa mts. Fabaceae Lotus procumbens TR, PR, DMoj Little San Bernardino Mts. north Fagaceae Quercus douglasii Teh, WTR (n slope) Fagaceae Quercus Xalvordiana Teh Grossulariaceae Ribes cereum var. cereum Ribes cereum var. cereum Teh, TR, SnJt, DMtns 8 Hydrophyllaceae Phacelia ixodes RARE in CA; s SCo (San Diego County) Report was in Border Field State Park, not vouchered 8 Hydrophyllaceae Phacelia pachyphylla D Kern County to Imperial County Hydrophyllaceae Phacelia tanacetifolia SW (exc ChI), DMoj Krameriaceae Krameria parryi -- No taxon exists with this name Loasaceae Mentzelia tricuspis e DSon; DMtns e Mojave, esp about Needles Munz distribution is from red Munz; taxon not in blue Munz Loasaceae Mentzelia tricuspis var. brevicornuta Mentzelia brevicornuta -- DMoj (Red Rock Canyon, Kern Co. to Daggett and Newberry Mtns, San Bernardino Co.) Munz distribution is from red Munz; taxon not in blue Munz Loasaceae Mentzelia tridentata c DMoj Malvaceae Sphaeralcea emoryi var. emoryi s DMoj, DSon vouchers are in Riverside, Imperial and San Bernardino Counties, but not San Diego County Malvaceae Sphaeralcea orcuttii s DSon 9 Nyctaginaceae Boerhavia diffusa -- Boerhavia diffusa is apparently not native to California, nor found in California. USDA site gives it only as close as Texas 8, 9, 16 Onagraceae Camissonia arenaria DSon vouchers are all Imperial County except for one in Riverside County Onagraceae Camissonia boothii ssp. decorticans WTR Polygonaceae Eriogonum wrightii var. trachygonum -- n. Los Angeles County to n. California Rhamnaceae Condalia globosa var. pubescens DSon 24 vouchers in Imperial County; 1 each in Riverside and San Bernardino Counties Rhamnaceae Ziziphus obtusifolia var. canescens Condaliopsis lycioides DSon vouchers in Riverside, San Bernardino and Imperial Counties Rosaceae Potentilla rivalis Potentilla rivalis var. millegrana SnBr Bottom Lands, as along Colorado River, scattered stations in Calif. Scrophulariaceae Castilleja exserta ssp. venusta Orthocarpus purpurascens var. ornatus w DMoj Liliaceae Calochortus venustus Calochortus venustus WTR, SnGb There is a voucher near Mountain Springs Grade, but that may be in Imperial County since it is not in the San Diego County checklist 9 Orchidaceae Platanthera sparsiflora Habenaria sparsiflora TR, PR
Rejected Taxa That Occur In San Diego County, But Not In The Desert
The following taxa had no voucher from the SDNHM Herbarium cited by Clemons, and no voucher could be located for them in the desert portion of San Diego County in online databases. (See procedure for checking for a voucher given above.)
If Clemons indicated the existence of a voucher from the Anza-Borrego Desert State Park Herbarium, that column is so marked. It is possible that these taxa were from the montane areas of the Park, as is the case for Pinus jeffreyi.
Some of these taxa are probably misidentifications, or incorrectly updated names given in Clemons' sources, such as Oenothera elata ssp. hookeri. It seems obvious that the older names of Oenothera hookeri might update to that taxon, but it almost always updates to Oenothera elata ssp. hirsutissima.
The column labeled Beauchamp distribution occasionally includes information from other sources, such as the Jepson Manual or San Diego County Plant Atlas, which are so labeled.
An entry in the column labeled AB means that Clemons reported that there was a voucher for that taxon present at the Anza-Borrego Desert State Park Herbarium.
Family Scientific Name Clemons Name (if different) AB Beauchamp distribution Selaginellaceae Selaginella asprella scarce, on rocky eastern slopes of Laguna Mtns; montane above 1650 m Selaginellaceae Selaginella cinerascens coastal, below 300 m Pinaceae Pinus coulteri AB montane above 1200 m Pinaceae Pinus jeffreyi montane above 1200 m; Clemons only gives this in Area 26 Pinaceae Pinus lambertiana montane above 1350 m; Clemons only gives this in Area 26 Amaranthaceae Amaranthus californicus montane, above 800 m Amaranthaceae Amaranthus retroflexus cismontane Apiaceae Anethum graveolens coastal, below 400 m Asteraceae Achyrachaena mollis cismontane below 700 m Asteraceae Agoseris grandiflora montane, above 900 m Asteraceae Baccharis pilularis Baccharis pilularis ssp. conssanguinea coastal below 200 m Asteraceae Cotula australis cismontane below 200 m Asteraceae Encelia californica coastal below 150 m Asteraceae Gutierrezia microcephala introduced by Caltrans at Buckman Springs Asteraceae Helianthus annuus Helianthus annuus ssp. lenticularis unconfirmed voucher jb2#652 U28 Asteraceae Hemizonia conjugens coastal below 100 m Asteraceae Isocoma menziesii var. vernonioides Haplopappus venetus var. vernonioides San Diego Plant Atlas: unverified voucher jb2#642 in grid U28 Boraginaceae Plagiobothrys collinus var. californicus Plagiobothrys californicus var. californicus coastal and foothill below 500 m Brassicaceae Lepidium virginicum var. robinsonii coastal and foothill below 700 m Ericaceae Arctostaphylos otayensis foothill, 200-900 m, Otay, San Miguel, Jamul and Guatay Mountains Euphorbiaceae Eremocarpus setigerus cismontane, below 1550 m; Potrero (area 6 western boundary) Fabaceae Hoita orbicularis Psoralea orbicularis montane above 1100 m Fabaceae Lupinus formosus var. bridgesii foothill and coastal below 800 m Fabaceae Thermopsis macrophylla var. semota AB montane above 1200 m Fagaceae Quercus kelloggii montane, above 1050 m Grossulariaceae Ribes amarum AB montane above 1200 m Grossulariaceae Ribes malvaceum AB not in Beauchamp: very rare in San Diego County; probably coastal Hydrophyllaceae Phacelia imbricata ssp. patula montane and foothill above 900 m Hydrophyllaceae Phacelia stellaris Phacelia douglasii var. cryptantha coastal, below 30 m Lamiaceae Salvia clevelandii coastal and foothill, below 1000 m Lamiaceae Trichostema lanatum foothill and coastal below 700 m Limnanthaceae Limnanthes gracilis ssp. parishii montane, above 1300 m Loasaceae Mentzelia gracilenta cismontane above 500 m Onagraceae Camissonia bistorta Camissonia bistorta var. veitchiana cismontane below 1400 m Onagraceae Camissonia intermedia Oenothera micrantha var. exfoliata foothill, 100-300 m Onagraceae Clarkia delicata foothill, 150-1300 m Onagraceae Oenothera elata ssp. hookeri AB JM: coastal bluffs Polemoniaceae Allophyllum glutinosum AB cismontane below 1500 m Polemoniaceae Eriastrum filifolium Linanthus filifolium; Gilia filiflolia; Langloisia filifolium coastal and foothill, below 700 m Polemoniaceae Gilia capillaris rare, montane, above 1500 m: Doane Valley, Palomar Mountain Polemoniaceae Gilia ochroleuca ssp. exilis Gilia ochroleuca ssp. exilis unverified mrm#1032 in k29 Polemoniaceae Linanthus orcuttii AB montane above 1400 m Polemoniaceae Navarretia atractyloides Navarretia hamata ssp. foliacea foothill, 200-800 m Polygonaceae Chorizanthe procumbens Chorizanthe procumbens var. albiflora coastal and foothill, below 800 m Polygonaceae Eriogonum fasciculatum var. fasciculatum coastal and foothill; an indicator of coastal sage scrub Primulaceae Anagallis arvensis coastal and foothill, below 1100 m Ranunculaceae Delphinium hesperium ssp. cuyamacae montane, above 1200 m Ranunculaceae Ranunculus californicus Ranunculus californicus var. ludovicianus coastal, foothill and montane Ranunculaceae Ranunculus canus Ranunculus canus var. ludovicianus unlikely; only known from lake henshaw Ranunculaceae Thalictrum fendleri var. fendleri Thalictrum fendleri montane, above 1200 m Rhamnaceae Ceanothus spinosus cismontane Rhamnaceae Rhamnus pilosa foothill, 300-700 m Rosaceae Amelanchier utahensis Amelanchier pallida montane coniferous forest, above 1050 m Rosaceae Fragaria vesca Fragaria californica AB montane above 1200 m Rosaceae Prunus virginiana var. demissa Prunus virginiana montane coniferous forest, above 1000 m Rubiaceae Galium nuttallii ssp. nuttallii coastal and foothill, below 500 m Scrophulariaceae Cordylanthus rigidus ssp. setigerus Cordylanthus filifolius cismontane Sterculiaceae Fremontodendron mexicanum AB foothill Ulmaceae Celtis reticulata rare; montane valleys; 1200-1500 m Violaceae Viola purpurea ssp. purpurea Viola purpurea montane Viscaceae Arceuthobium campylopodum AB montane above 1000 m Juncaceae Juncus oxymeris AB foothill and montane Juncaceae Juncus rugulosus cismontane Liliaceae Brodiaea orcuttii coastal and foothill, below 1500 m Liliaceae Calochortus dunnii foothill and montane, above 1000 m Poaceae Agrostis exarata cismontane, above 500 m Poaceae Calamagrostis koelerioides Calamagrostis densa foothill and montane, above 400 m Poaceae Hordeum murinum ssp. glaucum Hordeum glaucum no locations or vouchers in the desert from Beauchamp, which seems surprising Poaceae Vulpia microstachys var. ciliata Festuca grayi rare, in interior valleys
Taxa Without Vouchers In The Original Checklist That Now Have Vouchers
These taxa were listed in the original Checklist as being only reported, without a voucher present at the SDNHM Herbarium. I have used the procedure for checking for a voucher given above and either found a voucher for each taxon, or a location cited in Beauchamp. As detailed above, I used Beauchamp as a proxy for the possible existence of a voucher at the SDNHM Herbarium since I do not have access to an electronic list of vouchers from there. An AB in the Voucher column indicates that Clemons reported a voucher present at the Anza-Borrego Desert State Park Herbarium.
Note the caveat given in the description of the procedure about vouchers from the San Diego County Plant Atlas in grid cells that are not completely contained within Area 7 or 9. Those grid cells are R26, S26, T26 and U26 for Area 7; and G20, H20, I21, J21, K21, L22, M22, N23, O24, P24, Q24 and R24 for Area 9. Taxa with vouchers only from the Plant Atlas in those areas may not actually be in Areas 7 and 9. When I get the complete data from the Plant Atlas for those cells, I'll do that check.
Family Scientific Name Clemons Name (if different) No Voucher Voucher or Beauchamp distribution Azollaceae Azolla filiculoides JEPS302; e; Grapevine Spring Warner Pass Pteridaceae Pentagramma triangularis ssp. triangularis Pityrogramma triangularis ssp. triangularis; Pityrogramma triangularis POM172805 Borrego Palm Canyon 1200 feet; POM97254 San Felipe Creek at Banner, Alt. 3000 ft; POM98185 Vallecito Canyon, Laguna Mountains, Alt. 3700 ft Ephedraceae Ephedra trifurca POM122739 Yaqui Well; Mountain Springs Amaranthaceae Amaranthus palmeri X San Felipe Valley; JEPS89086 Cameron Lake Colorado Desert 1901 Apiaceae Yabea microcarpa Caucalis microcarpa; Yabea microcarpa UCR155753 Jon P. Rebman In-Ko-Pa Mtns Jacumba Natural Area, at top of grade along the road to Valley of the Moon, just E of the microwave towers; UCR157192 Walker Canyon Ecological Reserve (Ca. Dept. of Fish & Game): between Boulevard and Jacumba on the north side of Interstate 8, Asteraceae Ambrosia psilostachya Ambrosia psilostachya var. californica UCR156174 Walker Canyon Ecological Reserve: between Boulevard and Jacumba on the north side of Interstate 8; leh#201 J23; Asteraceae Artemisia ludoviciana ssp. ludoviciana Artemisia ludoviciana ssp. gnaphalodes jr#11895 T27 Asteraceae Chaenactis artemisiifolia JEPS9036 2 1/2 mi below (se of) San Felipe Store San Felipe Valley; leh#49 E25 Asteraceae Chaenactis xantiana SJSU14643 Old Kane Springs Rd between Split Mt & Borrego Springs Rds, SE of Borrego Springs Asteraceae Cirsium occidentale var. californicum Cirsium californicum jr#8668 T27; jtd#25 M22 Asteraceae Ericameria parishii var. parishii Haplopappus arborescens ssp. parishii leh#234 K21 Asteraceae Gnaphalium canescens ssp. beneolens Gnaphalium beneolens RSA705579 Walker Canyon Ecological Reserve (Ca. Dept. of Fish & Game): between Boulevard and Jacumba on the north side of Interstate 8 Asteraceae Gutierrezia sarothrae jb2#699 in Grid G25; jr#10771 in T27 Asteraceae Hulsea californica POM159612 Colorado Desert; Western Colorado Desert region San Felipe Asteraceae Lactuca serriola Lactuca serriola f. integrifolia; Lactuca serriola jr#11908 T27; unverified leh#956 I21; rh#30 E24 Asteraceae Lepidospartum squamatum RSA678065 Clark Valley Asteraceae Machaeranthera asteroides var. lagunensis Machaeranthera lagunensis POM244868 Jacumba Asteraceae Machaeranthera juncea Haplopappus junceus SBBG62783 Jacumba Asteraceae Malperia tenuis JEPS85829 Ocotillo Wells Asteraceae Stephanomeria virgata ssp. virgata Stephanomeria virgata UC507798 Mountain Springs Grade 1917 Asteraceae Stylocline gnaphaloides X Borrego Palm Canyon; Scissors Crossing; southeast corner of county Asteraceae Xanthium strumarium Xanthium strumarium var. strumarium; Xanthium pennsylvanicum JEPS37536 sandy wash San Felipe Creek Berberidaceae Berberis fremontii UC135595 Jacumba Berberidaceae Berberis nevinii X San Felipe Wash Boraginaceae Cryptantha holoptera X AB; Split Mountain Boraginaceae Cryptantha utahensis jr#11298 and leh#78 in grid S29 Boraginaceae Plagiobothrys canescens X San Felipe Ranch Brassicaceae Erysimum capitatum ssp. capitatum Erysimum capitatum X AB; Culp Valley Cactaceae Echinocereus engelmannii JEPS66848 San Felipe Valley; RSA436372 Lower Borrego Valley Cactaceae Opuntia parryi Opuntia parryi var. parryi POM288520 2 miles east of Banner, San Felipe Valley. Colorado Desert. Alt: 2500 ft. Cactaceae Opuntia phaeacantha Opuntia littoralis var. piercei UCR108010 Peninsular Range East of Boulevard; between Jacumba and Boulevard along old Hwy 80; UCR108033 San Felipe Valley Wildlife Refuge, NE of Julian, along Hwy S-2, N of Hwy 78. Campanulaceae Nemacladus ramosissimus JEPS17872 0.3 mi e; along State Hwy 78 Anza State Park w border Anza State Park Capparaceae Wislizenia refracta ssp. palmeri Wislizenia refracta JEPS13993 Borrego Valley; central part Borrego Valley; POM153427 Borrego Valley. Caryophyllaceae Silene gallica RSA121898 Colorado Desert: Western Colorado Desert region Cholla Ranch, San Felipe Valley. Alt: 2000 ft. Caryophyllaceae Spergularia platensis X Carrizo Creek, below 200 m Chenopodiaceae Salsola tragus Salsola iberica SJSU14626 Henderson Canyon Rd N of Borrego Springs; UC1282044 200 yds. w. of State Hwy. 78 bridge over; Sentenac Canyon San Felipe Creek Sentenac Canyon Cistaceae Helianthemum scoparium Helianthemum scoparium var. aldersonii; Helianthemum scoparium var. vulgare UC189103 San Felipe; jg#874A S27 Cucurbitaceae Cucurbita foetidissima UCR108049 Peninsular Range San Felipe Valley Wildlife Refuge, NE of Julian, along Hwy S-2, N of Hwy 78; leh#924 I21 Euphorbiaceae Chamaesyce serpyllifolia ssp. serpyllifolia Euphorbia serpyllifolia X Jacumba Euphorbiaceae Tetracoccus dioicus X coastal and foothill, below 1000 m; Jacumba Fabaceae Astragalus aridus JEPS51252 Vallecito; dry mesas Vallecito ; POM26390 Colorado Desert; Southern Colorado Desert region Borrego Spring Fabaceae Astragalus magdalenae var. peirsonii RSA705180; Blow Sand Canyon, NE side of Borrego Mountain, ca. 3 mi N of Ca Hwy 78 Fabaceae Astragalus sabulonum X AB; Borrego Springs; Split Mountain; Scissors Crossing Fabaceae Cercis occidentalis X AB; Banner; Oriflamme Canyon; Vallecito Trail Fabaceae Hoita macrostachya Psoralea macrostachya UC1087453 Vallecitos Creek Canyon; beauchamp says san felipe Fabaceae Lotus scoparius var. scoparius X Banner grade Fabaceae Lupinus excubitus var. medius X AB; The Potrero; Canebrake Canyon; Rockhouse Canyon; Carrizo Gorge; Table Mountain; McCain Valley Hydrophyllaceae Nemophila menziesii var. menziesii X foothill and montane, above 800 m; Culp Valley; Montezuma View Point Hydrophyllaceae Phacelia campanularia ssp. campanularia X Borrego Palm Canyon, Grapevine Spring; Sentenac Canyon; etc. Hydrophyllaceae Phacelia ivesiana X AB: Rare; Borrego Springs Malvaceae Herissantia crispa X AB; Rare; Mountain Springs Grade Malvaceae Malacothamnus densiflorus Malacothamnus densiflorus var. densiflorus RSA289177 Foot of Banner Grade, San Felipe Valley, Hiway 78, E of Julian Nyctaginaceae Mirabilis californica Mirabilis californica var. californica X gk#7 unverified k24; hellhole canyon; mountain springs; potrero Nyctaginaceae Mirabilis tenuiloba CSH11,111 Palm Canyon 1.5 mi above Park Hdqtrs, Anza Borrego State Park; JEPS61350 *grade e of Mountain Springs ; UCR98418 Carrizo wash Onagraceae Camissonia hirtella X San Felipe Valley; Jacumba Onagraceae Camissonia micrantha RSA337491 Anza-Borrego Desert State Park; along road leading to Palm Springs [Hwy S2] near West Mesa of Carrizo Badland; 620 feet elevation.; Onagraceae Camissonia pallida ssp. hallii ds2#16 in grid K24 Onagraceae Clarkia purpurea ssp. quadrivulnera X AB; Chariot Canyon on border of 9 Polemoniaceae Eriastrum densifolium ssp. austromontanum UC133824 Jacumba; POM6689 Jacumba; UC507843 Mountain Springs Grade Polemoniaceae Gilia micromeria SD 120950: McCain Valley, Clemons & Jonsson 1699 Polemoniaceae Ipomopsis tenuifolia JEPS13790 betw Mountain Springs and Jacumba Polemoniaceae Linanthus parviflorus Gilia lutea; Linanthus lutea var. longistylis; Linanthus androsaceus ssp. luteolus CHSC1273 Sentenac Canyon near Julian Polygonaceae Chorizanthe staticoides Chorizanthe staticoides ssp. staticoides; Chorizanthe discolor UCR113963 San Felipe Valley San Felipe Valley Wildlife area, E of Julian. Along Hwy S2, ca. 4.5 mi N of Hwy 78 Polygonaceae Eriogonum angulosum X coastal and desert, below 400 m: Borrego Palm Canyon; San Felipe Wash; Mountain Springs; Jacumba Polygonaceae Eriogonum fasciculatum var. foliolosum UC507779 Mountain Springs Grade jb2#8 in K21 Polygonaceae Eriogonum ordii UC77324 Split Mt. Colorado Desert, known only from split mtn, which is on the boundary between areas 8 and 16 Polygonaceae Nemacaulis denudata var. gracilis X Clemons just gave the species in areas 7 and 9; only gracilis is desert; Carrizo Creek Salicaceae Salix lasiolepis UC1087422 near; near bridge, on hillside and flat of stream Jacumba Hot Springs UCR108024 San Felipe Valley Wildlife Area: NE of Julian, ca. 4.5 mi. N of Hwy 78 on Hwy S-2; between the Volcan Mountains and San Felipe Hills Saururaceae Anemopsis californica X AB; Sentenac Canyon; Vallecito Stage Station; Boulevard Scrophulariaceae Antirrhinum filipes CHSC36009 10 miles NW of Borrego Springs at trail end near Salvidore Canyon; JEPS5313 Vallecito; w Colorado Desert JEPS5314 San Felipe Creek Sentenac Canyon Scrophulariaceae Antirrhinum nuttallianum ssp. nuttallianum Antirrhinum nuttallianum; Antirrhinum nuttallianum f. pusillum JEPS83397 just w; Hwy 94, w end of bridge over railroad tracks, on n side of road along railroad tracks Jacumba Jacumba Quad. (7.5', 1959) Scrophulariaceae Castilleja affinis ssp. affinis UCR116035 Peninsular Range Jacumba Valley, ca. 2 mi. N of Jacumba on railroad road Scrophulariaceae Mimulus palmeri Mimulus diffusus X McCain Valley Scrophulariaceae Mimulus rubellus X rare; 900-1200 m; Vallecito Canyon Scrophulariaceae Penstemon clevelandii var. clevelandii RSA670399 Colorado Desert; Western Colorado Desert region Narrows E. of Yaqui Well. Alt: 500m. UC55925 Coyote Canyon; western borders of the Colorado Desert; RSA264566 Peninsular Ranges; Cuyamaca-Laguna Mountains region Slope above Bankhead Springs, 5 mi. nw of Jacumba SE San Diego County, CA Scrophulariaceae Penstemon clevelandii var. connatus X AB: Vallecito Canyon Scrophulariaceae Penstemon spectabilis var. spectabilis Penstemon spectabilis UC1408720 s Jacumba Mexican Boundary, s of Jacumba Scrophulariaceae Penstemon Xparishii (P. centranthifolius X P. spectabilis var. spectabilis) X Beauchamp: Hipass; Lost Valley Solanaceae Datura discolor am2#5 I16 Solanaceae Datura wrightii Datura meteloides bbs#86 in D24; jr#10059 in T27 Solanaceae Lycium parishii JEPS8051 e face of; in canyon of Mountain Palm Springs, Anza Desert State Park, e San Diego County Tierra Blanca Mountains Solanaceae Physalis hederifolia var. fendleri Physalis hederifolia var. cordifolia X scarce, desert and foothill, 800-1200 m; Jacumba; near Walker Ranch Solanaceae Solanum nigrum X San Felipe Tamaricaceae Tamarix aphylla X Borrego Valley Cyperaceae Cyperus laevigatus X Beauchamp: Palm Spring; Bow Willow Canyon Cyperaceae Eleocharis montevidensis UC1100715 Jacumba Juncaceae Juncus balticus mrm#1331 in T27 Juncaceae Juncus bufonius var. bufonius Juncus bufonius X Canebrake Canyon Lemnaceae Lemna aequinoctialis 2 vouchers from Lakeside and Vallecitos Canyon by Landolt Lemnaceae Lemna valdiviana POM48412 Peninsular Ranges; Cuyamaca-Laguna Mountains region Vallecito Canyon, Laguna Mountains, Alt. 3500 ft. Liliaceae Chlorogalum parviflorum leh#850 in Grid I21 Poaceae Aristida californica var. californica Aristida californica JEPS75611 San Felipe Narrow; POM117001 Colorado Desert; Western Colorado Desert region Canyon west of Borrego Spring. Alt. 1500 ft. Poaceae Aristida purpurea var. parishii Aristida parishii CHSC60199 At Yaqui Well Camp Ground in Anza-Borrego Desert Park Poaceae Digitaria sanguinalis X Montezuma Valley Poaceae Erioneuron pulchellum X AB; ne corner of county; fish creek; mountain palm springs; etc. Poaceae Nassella cernua Stipa cernua UCR108293 Anza-Borrego Desert State Park: 1 mile NE of Padre Fages marker on Hwy S-1; UCR156164 Walker Canyon Ecological Reserve: between Boulevard and Jacumba on the north side of Interstate 8, along arroyo bottom near the western end of the reserve. San Diego Atlas Square T27 Poaceae Nassella pulchra Stipa pulchra X sw cismontane; also Jacumba Poaceae Sporobolus cryptandrus UCR108054 Peninsular Range San Felipe Valley Wildlife Refuge, NE of Julian, along Hwy S-2, N of Hwy 78. Poaceae Sporobolus flexuosus mrm#1333 in Grid T27; SBBG56979 in San Felipe Valley Poaceae Vulpia bromoides Festuca dertonensis; Vulpia dertonensis jr#11385 in T27
Taxa Approaching the Area
The following taxa are not found in the 2001 or 2006 San Diego County Checklist, but have vouchers extremely close to the desert portion of San Diego County. Future searches might find these taxa within San Diego County.
Family Scientific Name # Riverside Co. Vouchers #Imperial County Vouchers Nearest Voucher Fabaceae Astragalus magdalenae var. peirsonii 32 0 miles?; Voucher in San Diego County: RSA705180; Blow Sand Canyon, NE side of Borrego Mountain, ca. 3 mi N of Ca Hwy 78, but not accepted by Rebman and Simpson; otherwise, 47 miles; Algodones Dunes near Holtville (UC495108) Onagraceae Camissonia arenaria 1 11 2 miles; Salton Sea near Oasis (POM66476) Loasaceae Mentzelia tricuspis 2 2 3 miles; foot of Mt. Springs grade (JEPS2647) Hydrophyllaceae Phacelia pachyphylla 3 6 miles; Painted Gorge, Imperial County (UCR98422, UCR41689, UC650709) Malvaceae Sphaeralcea emoryi var. emoryi 9 10 14 miles; SR86 between Kane Spring and San Felipe Creek (UCR150428) Cucurbitaceae Brandegea bigelovii 55 22 15 miles: 5 air mi. S of Palm Desert near top of Seven Level Hill (CHSC25967); Mecca Hills; Painted Canyon (JEPS42503) Euphorbiaceae Chamaesyce platysperma 1 15 miles; Superstition Mountain (RSA480961); also report in JM for Coachella Valley, but no online voucher for it Poaceae Aristida purpurea var. wrightii 2 22 miles; Cottonwood Spring, Riverside County (UC815792) Rhamnaceae Ziziphus obtusifolia var. canescens 18 4 24 miles; Cottonwood Spring, Riverside County (JEPS41934) Amaranthaceae Amaranthus watsonii 1 5 34 miles; near Calexico (POM155936) Rhamnaceae Condalia globosa var. pubescens 1 24 36 miles; Chuckwalla Bench W side of Chuckwalla Mtns, 9 miles S of Hwy I-10 on the Gasline Road, 2 mi. airline S of the Model Mine (UCR41565 ) Lennoaceae Pholisma sonorae 26 42 miles; 10 miles east town of Brawley (RSA209611) Apiaceae Ammoselinum giganteum 2 50 miles; Chuckwalla Valley, Riverside County (JEPS14148, UC1046273)
Number of Taxa by Floristic Area
The following table summarizes the number of taxa by voucher status and by Floristic Area:
Voucher Status # Taxa in Each Floristic Area 7 8 9 16 Reported 103 86 79 91 Vouchered 395 306 500 333 Beauchamp 14 9 17 9 Total 512 401 596 433
The total numbers for each Floristic Area are plotted below, with a curve drawn from a fit to San Diego County as a whole considering only native taxa. The first plot shows just the numbers for these four Floristic Areas and the fit; the second plot includes numbers from many different floras for regions in coastal Southern California.
One expects the desert to have lower overall numbers of species than coastal areas, so these numbers for Areas 7, 8 and 9 look quite reasonable. The numbers for Area 16 look quite low. This may simply represent the lack of varied terrain over most of Area 16, or, more likely, the lack of study of the areas of the Santa Rosa Mountains and the Vallecito Mountains.
The number of taxa found only in a single Area, only in two Areas, only in three Areas, or in all four Areas is given in the next table:
# Areas # Taxa Found Only in that # Areas 1 262 2 215 3 182 4 176
This is an unusual distribution. Normally, the number of taxa found in n areas decreases rapidly for larger values of n. See, for example, How Common Are The Plants Of Southern California? or the distribution for the Santa Monica Mountains.
This unusual distribution indicates either that the lists for individual Areas are incomplete, missing a lot of species found only in individual areas, or that the flora in the desert is much more uniform than in cismontane areas. The answer is probably a bit of both.
Due to the size of the Checklist, it is on a separate webpage.
Copyright © 2006 by Tom Chester
Permission is freely granted to reproduce any or all of this page as long as credit is given to me at this source:
Comments and feedback: Tom Chester
Last update: 13 March 2006 (Table titled Rejected Taxa That Do Not Occur In San Diego County updated on 18 December 2009 to correct error in Family Name column