Plant Species of the Borrego Desert: The Nifty Fifty: The 51 Most Common Species


Table of Contents

Introduction
Analysis of the List
The Checklist
     Sort by Abundance
     Sort by Family


Introduction

The page gives the most common 51 species of the Borrego Desert. Those top 51 species are defined as those occurring in nine or more of the 24 individual surveys I've done as of 29 December 2008. (OK, one more than 50, but Nifty Fifty sounds better than Nifty Fifty-one, and matches the name of the popular common stocks of the 1960s and 1970s. Artistic license, you know.)

Caution: this list is preliminary, and should not be used for scientific purposes until I've finished my flora of the Borrego Desert. In particular, the results may change in the future as more fieldwork is done and more of my previous fieldwork is digitized, especially as more survey locations are added and more fieldwork is done when annuals are present.

To help understand what this list represents, it may help to understand examples of what this list does not represent:

For example, this list does not contain many of the common species found in the sandy habitat along Henderson Canyon and Di Giorgio Roads such as hairy sand verbena, Abronia villosa; desert dicoria, Dicoria canescens; and hairy desert-sunflower, Geraea canescens. Those species have been found, respectively, in only 2, 5, and 2 of my 24 surveyed areas so far. Although those species are both common and widespread because their habitat is common and widespread along the desert floor, their habitat is not found in most of my surveyed areas, and thus these species don't make the list here.

This example of plants confined to a specific habitat gives insight into what the list presented here actually represents. Most species are like the three species mentioned above, confined to a single habitat. Examples of habitats and species confined to that habitat, along with the number of survey areas in which each named species was found, are given in the following table:

HabitatSpecies confined to that Habitat#
Survey
Areas
Common NameScientific Name
Gravelly washes subject to flooding that scarifies seedssmoke treePsorothamnus spinosus13
Moderately saline areasfour-wing saltbushAtriplex canescens8
Steep canyon walls of solid rockarrow-leafPleurocoronis pluriseta6
Seeps, springs, streamsidesCalifornia fan palmWashingtonia filifera3
Rocky slopes among boulderspygmy-cedar Peucephyllum schottii3
Sandy placeshairy sand verbenaAbronia villosa2
Extremely saline areasiodine-bushAllenrolfea occidentalis2
Permanent streamsFremont cottonwoodPopulus fremontii2

Of the species in the above table, only smoke tree, Psorothamnus spinosus, exceeds the cutoff of 9 or more survey areas and is present the top 51 list here. Even though it is confined to a very specific habitat, that habitat is widespread through my surveyed areas. Four-wing saltbush, Atriplex canescens, just misses the cut-off. Its habitat of moderately saline areas is fairly widespread, but not quite enough to make the cutoff here.

In addition, many species are confined to geographic habitats with specific sets of conditions. Some of these habitats can be easily understood by mere mortals, such as the species that are confined to the Desert Transition Zone near the east base of the Peninsular Range where they find the only combination of heat, rainfall and cold that they can thrive in. Examples are desert apricot, Prunus fremontii; and lotebush, Ziziphus parryi, each found in two surveyed areas. Other species seem to be confined to specific habitats that are hard for humans to comprehend.

To see what the list does represent, here are the habitats of the two species found in all 24 surveyed areas. Burroweed, Ambrosia dumosa, is said to grow in Creosote Bush Scrub, meaning it grows essentially everywhere that the other top species, creosote, Larrea tridentata, grows. Creosote gives its name to its plant community, since it grows almost everywhere in the Sonoran desert, thriving in or at least tolerating a large number of habitats, under many different geographic conditions.

Those two species are not picky about where they grow, and are among the small number of species that successfully grow in many different conditions. In fact, Forrest Shreve, in Vegetation and Flora of the Sonoran Desert, says that these two species vastly outnumber all others in the Lower Colorado Valley subdivision, which includes the Borrego Desert (p. 49). The primary reason for this dominance is that these are the last two shrub species to drop out as the rainfall diminishes.

Note that such widespread common species are rare; see the histogram below that demonstrates the well-known biological law that common species are few in number; rare species are common in number.

Many of the other species on the list are similar non-picky species, but many others occur in specific habitats that are found in nearly every surveyed areas, such as smoke tree. Other examples are cheesebush, Hymenoclea salsola; and desert-lavender, Hyptis emoryi, which grow in any wash that has enough seasonal moisture for them.

Important Caveats:

The following map of the Borrego Desert shows where the surveys have been conducted so far:

Each dot roughly corresponds to the midpoint of each survey. Most of these surveys are detailed in preliminary Floras and Plant Trail Guides.

Each survey typically covered a linear distance of four miles or so, sometimes along a single trail and sometimes along a loop. The elevations surveyed ranged from 200 feet in the extreme northeast corner of the county, to 2600 feet in Hellhole Canyon. The mean elevation of the surveys was 1000 feet, with most of the area surveyed between 500 and 1500 feet. Note that the map above shows the 1000 foot and 3000 foot elevation contours.

This page can be used by beginning students of the Borrego Desert flora as a list of species to learn first, as well as by photographers trying to learn the species name for a common flower they photographed without having to wade through the 373 species I've observed so far, or the 641 species including records from others from this entire area. People familiar with the Borrego Desert can check to see if they know all of the top 51 species.

For those itching to know the next most common species, see The 172 Most Common Species, which includes the top 51 species.

Analysis of the List

The following histogram gives the number of surveys in which each taxon was found:

This histogram follows the usual shape, in which only a very few species are ubiquitous, with most species being found in only one or two surveys. Hence the statement above that common species are few in number; rare species are common in number. For more information on how this histogram was derived, and why this is the usual shape, see How Common Are The Plants Of Southern California? and Plants of Southern California: Introduction and Explanation of Trail Guides. The plotted curve through the data points is a fairly good fit, indicating that survey incompleteness is not a significant factor overall.

The following histogram gives the number of species in this list by plant habit, sorted first alphabetically by habit and then sorted by abundance:

Sort Alphabetically By Habit Sort Numerically By Abundance
HabitH#% HabitH#%
AnnualA1835%                        AnnualA1835%
CactusC612%            Shrub / SubshrubS1733%
FernF12%            PerennialP816%
PerennialP816%            CactusC612%
Shrub / SubshrubS1733%            FernF12%
TreeT12%            TreeT12%

The column H gives the abbreviation used for the plant habit in the checklists below.

The Checklist

The Nifty Fifty are presented in two ways below. In both versions, the Family and Scientific Name are from the Jepson Manual. An asterisk before the Common Name indicates a non-native taxon. #S is the number of surveys in which each taxon was found. H is the abbreviation used for the plant habit, given in the table above.

First, the checklist is presented in descending order of abundance, sorted by the number of surveys in which each taxon was found. Second, it is presented in traditional family order: sorted first by category - ferns, dicots, and monocots - and then by family and scientific name.

The checklist contains Krameria grayi, but not its sister species of Krameria erecta. These two species are very difficult to tell apart without fruit, which is not always present, and thus readers may wonder how common K. erecta is. K. erecta appears in 8 lists, and thus just missed the cutoff of 9, compared to the 18 lists that contained K. grayi.

This is a working list, about which I make no guarantees at all until I officially release it. Use at your own risk!

The Checklist Sorted by Abundance

Version for printing, without lines and other text on this page: html (2 pages) or pdf Clickbook booklet (1 double-sided pages). (See printing instructions for an explanation of these options)

##SHJM FamilyScientific Name(*)Common Name
124SAsteraceaeAmbrosia dumosaburroweed
224SZygophyllaceaeLarrea tridentatacreosote bush
323SFabaceaePsorothamnus schottiiindigo bush
422SAsteraceaeEncelia farinosabrittlebush
522PEuphorbiaceaeChamaesyce polycarpasmall-seeded spurge
622SFouquieriaceaeFouquieria splendens ssp. splendensocotillo
721SAsteraceaeHymenoclea salsola var. salsolacheesebush
821ABrassicaceaeBrassica tournefortii*Asian mustard
921AOnagraceaeCamissonia californicaCalifornia suncup
1021PPoaceaePleuraphis rigidabig galleta
1119SAsteraceaeBebbia juncea var. asperasweetbush
1219PAsteraceaeStephanomeria pauciflora var. pauciflorawire-lettuce
1319SFabaceaeAcacia greggiicatclaw
1419SLamiaceaeHyptis emoryidesert-lavender
1518SKrameriaceaeKrameria grayiwhite rhatany
1617CCactaceaeOpuntia basilaris var. basilarisbeavertail cactus
1717CCactaceaeOpuntia ganderiGander's cholla
1817APlantaginaceaePlantago ovatadesert plantain
1917PPolygonaceaeEriogonum inflatumdesert trumpet
2016CCactaceaeFerocactus cylindraceusCalifornia barrel cactus
2115AAsteraceaePerityle emoryiEmory's rock-daisy
2214AOnagraceaeCamissonia boothii ssp. condensataBooth's evening primrose
2314APolygonaceaeChorizanthe brevicornu var. brevicornubrittle spineflower
2414PViscaceaePhoradendron californicumdesert mistletoe
2513TFabaceaePsorothamnus spinosussmoke tree
2613AOnagraceaeCamissonia claviformis ssp. peirsoniibrown-eyed primrose
2713APoaceaeSchismus barbatus*Mediterranean schismus
2812ABrassicaceaeLepidium lasiocarpum var. lasiocarpumhairy-podded pepper-grass
2912CCactaceaeOpuntia echinocarpasilver cholla
3012AHydrophyllaceaePhacelia distanscommon phacelia
3112SZygophyllaceaeFagonia laevisCalifornia fagonia
3211AAsteraceaeRafinesquia neomexicanadesert chicory
3311CCactaceaeOpuntia bigeloviiteddy-bear cholla
3411PEuphorbiaceaeDitaxis lanceolatanarrowleaf ditaxis
3511AFabaceaeLupinus arizonicusArizona lupine
3611AHydrophyllaceaePhacelia crenulata var. ambiguaheliotrope phacelia
3711ALoasaceaeMentzelia involucratabracted blazing star
3811SLoasaceaePetalonyx thurberi ssp. thurberiThurber's sandpaper-plant
3911PMalvaceaeHibiscus denudatusrock hibiscus
4011PNyctaginaceaeMirabilis bigelovii var. retrorsawishbone plant
4110CCactaceaeOpuntia ramosissimapencil cholla
4210AFabaceaeLupinus concinnusbajada lupine
4310SFabaceaePsorothamnus emoryiEmory's indigo-bush
4410AGeraniaceaeErodium cicutarium*redstem filaree
4510ALamiaceaeSalvia columbariaechia
469AAsteraceaeSenecio mohavensisMojave ragwort
479SAsteraceaeTrixis californica var. californicaCalifornia trixis
489SBoraginaceaeTiquilia palmeriPalmer's coldenia
499SChenopodiaceaeAtriplex hymenelytradesert holly
509SChenopodiaceaeAtriplex polycarpacattle saltbush
519FPteridaceaeCheilanthes parryiwoolly lipfern

The Checklist Sorted by Family

Version for printing, without lines and other text on this page: html (2 pages) or pdf Clickbook booklet (1 double-sided pages). (See printing instructions for an explanation of these options)

##SHJM FamilyScientific Name(*)Common Name
19FPteridaceaeCheilanthes parryiwoolly lipfern
224SAsteraceaeAmbrosia dumosaburroweed
319SAsteraceaeBebbia juncea var. asperasweetbush
422SAsteraceaeEncelia farinosabrittlebush
521SAsteraceaeHymenoclea salsola var. salsolacheesebush
615AAsteraceaePerityle emoryiEmory's rock-daisy
711AAsteraceaeRafinesquia neomexicanadesert chicory
89AAsteraceaeSenecio mohavensisMojave ragwort
919PAsteraceaeStephanomeria pauciflora var. pauciflorawire-lettuce
109SAsteraceaeTrixis californica var. californicaCalifornia trixis
119SBoraginaceaeTiquilia palmeriPalmer's coldenia
1221ABrassicaceaeBrassica tournefortii*Asian mustard
1312ABrassicaceaeLepidium lasiocarpum var. lasiocarpumhairy-podded pepper-grass
1416CCactaceaeFerocactus cylindraceusCalifornia barrel cactus
1517CCactaceaeOpuntia basilaris var. basilarisbeavertail cactus
1611CCactaceaeOpuntia bigeloviiteddy-bear cholla
1712CCactaceaeOpuntia echinocarpasilver cholla
1817CCactaceaeOpuntia ganderiGander's cholla
1910CCactaceaeOpuntia ramosissimapencil cholla
209SChenopodiaceaeAtriplex hymenelytradesert holly
219SChenopodiaceaeAtriplex polycarpacattle saltbush
2222PEuphorbiaceaeChamaesyce polycarpasmall-seeded spurge
2311PEuphorbiaceaeDitaxis lanceolatanarrowleaf ditaxis
2419SFabaceaeAcacia greggiicatclaw
2511AFabaceaeLupinus arizonicusArizona lupine
2610AFabaceaeLupinus concinnusbajada lupine
2710SFabaceaePsorothamnus emoryiEmory's indigo-bush
2823SFabaceaePsorothamnus schottiiindigo bush
2913TFabaceaePsorothamnus spinosussmoke tree
3022SFouquieriaceaeFouquieria splendens ssp. splendensocotillo
3110AGeraniaceaeErodium cicutarium*redstem filaree
3211AHydrophyllaceaePhacelia crenulata var. ambiguaheliotrope phacelia
3312AHydrophyllaceaePhacelia distanscommon phacelia
3418SKrameriaceaeKrameria grayiwhite rhatany
3519SLamiaceaeHyptis emoryidesert-lavender
3610ALamiaceaeSalvia columbariaechia
3711ALoasaceaeMentzelia involucratabracted blazing star
3811SLoasaceaePetalonyx thurberi ssp. thurberiThurber's sandpaper-plant
3911PMalvaceaeHibiscus denudatusrock hibiscus
4011PNyctaginaceaeMirabilis bigelovii var. retrorsawishbone plant
4114AOnagraceaeCamissonia boothii ssp. condensataBooth's evening primrose
4221AOnagraceaeCamissonia californicaCalifornia suncup
4313AOnagraceaeCamissonia claviformis ssp. peirsoniibrown-eyed primrose
4417APlantaginaceaePlantago ovatadesert plantain
4514APolygonaceaeChorizanthe brevicornu var. brevicornubrittle spineflower
4617PPolygonaceaeEriogonum inflatumdesert trumpet
4714PViscaceaePhoradendron californicumdesert mistletoe
4812SZygophyllaceaeFagonia laevisCalifornia fagonia
4924SZygophyllaceaeLarrea tridentatacreosote bush
5021PPoaceaePleuraphis rigidabig galleta
5113APoaceaeSchismus barbatus*Mediterranean schismus


I thank Bill Sullivan for discussions which stimulated the extensive discussion in the Introduction about what this list does and does not represent.


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Copyright © 2009 by Tom Chester
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Last update: 10 January 2009