Plant Species of San Jacinto Mountain: Endemic Species

Fig. 1. Two SnJt endemic species and one SnJt near-endemic species growing side by side near the head of Andreas Canyon at the edge of Tahquitz Valley. Left: Tahquitz Ivesia, Ivesia callida, the only one in bloom in this pix. Middle: shaggy-haired alumroot, Heuchera hirsutissima. Right: cliff cinquefoil, Potentilla rimicola. Photo by James Dillane.
Click on the picture for a larger version.

There are 11 species which live only at San Jacinto Mountain (SnJt) and the Santa Rosa Mountains (SnRsMtns), plus a 12th species if it is accepted as a distinct species. Such species are called endemics, and are always fascinating to people since humans love rare things. If you want to see these endemic species, you can see them only here.

In addition, there are seven species where most of their population lives at SnJt and/or SnRsMtns, but which have a small number of individuals in neighboring areas, or in just one other location. These species are called near endemics.

The total number of endemic and near-endemic species is thus 18 or 19, depending on whether one species is accepted as a distinct species.

Twelve of these species are on CNPS List 1B - Plants Rare, Threatened, or Endangered in California and Elsewhere, and one more should be listed there, Keckiella rothrockii var. jacintensis, but for some reason is not; see webpage.

Table 1 lists the strictly-endemic species, and Table 2 lists the near-endemic species, in alphabetical order of their scientific name as given in the Jepson Manual second edition (JM2). The geographic range given is first the one in the JM2, expanded with notes. If we have a webpage on a given species, it is linked from the tables. The rarity codes for each species are also given, if they have ones.

See Information about the links from the Scientific Name and Common Name.

Table 1. Species Strictly Endemic to SnJt

#FamScientific NameCommon NameSnJt
CNPS | CA | Global
Geographic Range
1AsterDieteria canescens var. ziegleriZiegler's asterwebpage1B.2 S1 G5T1SnRsMtns
2BrassDraba saxosaSouthern California rock draba1B.3 S2 G2SnJt, SnRsMtns
3RubiaGalium angustifolium ssp. jacinticumSan Jacinto Mtns. bedstrawwebpage1B.3 S2? G5T2?w SnJt
4RubiaGalium californicum ssp. primumCalifornia bedstraw1B.2 S1 G5T1SCo, SnJt, but the SCo comes from just a single 1891 Parish voucher from "Reche Canyon" in San Bernardino County which may not be correctly located.
5SaxifHeuchera hirsutissimashaggy-haired alumrootwebpage1B.3 S3 G3SnJt, n SnRsMtns
6RosacIvesia callidaTahquitz ivesia1B.3 S1 G1SnJt, with just two locations known, one near 8000 feet below Tahquitz Peak, and one two miles away at the head of Andreas Canyon.
7PlantKeckiella rothrockii var. jacintensisSan Jacinto Mts. keckiellawebpageMissing!!SnJt
8PolemLeptosiphon floribundus ssp. halliiSanta Rosa Mtns. linanthus1B.3 S1S2 G4T1T2SnRsMtns
9PolemLinanthus jaegeriSan Jacinto prickly phlox1B.2 S2 G2SnJt
10PolygSidotheca emarginatawhite-margined oxytheca1B.3 S3 G3SnJt, SnRsMtns
11LamiaTrichostema austromontanum ssp. compactumHidden Lake bluecurls1B.1 S1 G3G4T1SnJt, with just a single known location at Hidden Lake.

Layia ziegleri, if this is accepted as a species, is a strict endemic. However, it is not accepted as a species in the JM2. Layia ziegleri was defined by Munz in 1969 in the Supplement to A California Flora, with type from grassy-meadowy slope between Mountain Center and Keen Camp Summit, at 4750 feet. He wrote:

This proposed species seems nearest to Layia glandulosa ssp. lutea and to L. pentachaeta. It resembles the former in its basal dentate leaves, entire cauline leaves, stipitate-glandular peduncles and involucres, ring of bracts between ray and disk fls, yellow anthers, setaceous pappus, etc., but differs in the more numerous subterete pappus-bristles which are scarcely plumose and not wholly at the base. From L. pentachaeta it differs in its involucre not being pustulate-hirsute and the less plumose pappus. From both taxa it is well removed geographically.

In the JM2, this species was synonymized with Layia platyglossa.

Table 2. Species Nearly Endemic to SnJt

#FamScientific NameCommon NameSnJt
CNPS | CA | Global
Geographic Range
12EricaArctostaphylos parryana ssp. deserticadesert Parry manzanitaPR (SnJt, SnRsMtns, San Ysidro Mtns). The vast majority of the population is at SnJt and SnRsMtns.
13BrassBoechera johnstoniiJohnston's rock cresswebpage1B.2S1G1B. johnstonii is endemic to SnJt if Arabis hirshbergiae is not merged with it. If they are merged, as done in the JM2, it is a near endemic, with the only other location near Cuyamaca Lake
14LiliaCalochortus palmeri var. munziiMunz's mariposa lilywebpage1B.2S3G3T3SnJt in JM2 (which includes SnRsMtns), but there are now a small number of vouchers from south of SnJt
15CelasEuonymus occidentalis var. parishiiParish's burning bushPR in JM2, but only two locations outside SnJt and SnRsMtns: Palomar Mtn State Park and Cuyamaca Rancho State Park
16AsterHulsea vestita ssp. callicarphabeautiful hulsea4.2S3G5T3near endemic to SnJt, SnRsMtns; other locations Palomar; Hot Springs Mtn; Cuyamaca Peak
17PlantPenstemon clevelandii var. connatusSan Jacinto beardtongue4.3S3G5T4e slope SnJt, SnRsMtns, but vouchers extend down the PR
18RosacPotentilla rimicolacliff cinquefoil2B.3S1G2SnJt, northern Baja. It appears to have only one other location, in the Sierra San Pedro Martir in Baja CA. There are only 3 vouchers of it from Mexico at SEINet.

Penstemon californicus is found only at SnJt in California, but it is found in the PR in nearly the entire length of the northern part of Baja Californica.

Rarity Code

If two neighboring codes are given for a taxon, such as T1T2, it indicates there is uncertainty as to whether it should be ranked T1 or ranked T2.

Citation for CNPS Rare Plant Ranks: CNPS, Rare Plant Program. 2016. Inventory of Rare and Endangered Plants (online edition, v8-02). California Native Plant Society, Sacramento, CA. Website [accessed 19 September 2016].

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Copyright © 2014-2017 by Tom Chester, Dave Stith and James Dillane.
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Updated 29 October 2017.