Rare & Endangered Plants

The California Native Plant Society (CNPS) Rare Plant Program

Statewide the program currently recognizes more than 1600 plant taxa (species, subspecies and varieties) as rare or endangered in California (CNPS Lists 1B and 2). This constitutes approximately 20% of California’s native flora. More than 500 additional species are on the CNPS list of plants of limited distribution (List 4, a “watch” list), and approximately 55 additional species are on the CNPS list of taxa about which we need more information (List 3). The Inventory also contains information on approximately 25 native plants that are presumed to have gone extinct in California in the last 100 years (primarily because of land conversion to agriculture and urban development). For more information see the CNPS  Rare Plant Program page “Rare Plant Program” http://www.cnps.org/cnps/rareplants/. 

Santa Clara Valley Chapter Rare Plants

The Santa Clara Valley Chapter of CNPS includes most of San Mateo County and all of Santa Clara County. San Mateo and Santa Clara County are endowed with an incredible richness of native plant species. This is due in part to our location that includes parts of the South Coast Ranges (Diablo Range), San Francisco Bay, Santa Cruz Mountains and the San Mateo Coast. Our botanical region provides unique ecological conditions and over 100 preserves with over 200,000 acres of natural areas and public lands, and approximately 1,300 native taxa.

There are 151 rare, threatened, and endangered vascular plants, 4 mosses and 1 lichen in San Mateo and Santa Clara County. Of those 7 are Federally-listed, 9 are Federally and State listed, and 7 are State-listed as endangered or threatened for a total of 23 taxa that are listed.

Below is our Rare Plant Table with some Plant Pages. We will be updating the table and adding more pages as they are finished. The Plant Pages were designed by Toni Corelli (This email address is being protected from spambots. You need JavaScript enabled to view it.) and Karen Tanner (This email address is being protected from spambots. You need JavaScript enabled to view it.). 

For comments or questions about the Plant Pages, contact Toni Corelli (This email address is being protected from spambots. You need JavaScript enabled to view it.).

Scientific Name	Common Name	Family	Lifeform	Photo and Plant Page (click for plant page)
Acanthomintha duttonii	San Mateo thorn-mint	Lamiaceae	annual herb
Acanthomintha lanceolata	Santa Clara thorn-mint	Lamiaceae	annual herb
Agrostis blasdalei	Blasdale's bent grass	Poaceae	perennial rhizomatous herb
Allium peninsulare var. franciscanum	Franciscan onion	Alliaceae	perennial bulbiferous herb
Allium sharsmithiae	Sharsmith's onion	Alliaceae	perennial bulbiferous herb
Amsinckia lunaris	bent-flowered fiddleneck	Boraginaceae	annual herb
Androsace elongata ssp. acuta	California androsace	Primulaceae	annual herb
Arabis blepharophylla	coast rockcress	Brassicaceae	perennial herb
Arctostaphylos andersonii	Anderson's manzanita	Ericaceae	perennial evergreen shrub
Arctostaphylos imbricata	San Bruno Mountain manzanita	Ericaceae	perennial evergreen shrub
Arctostaphylos montaraensis	Montara manzanita	Ericaceae	perennial evergreen shrub
Arctostaphylos pacifica	Pacific manzanita	Ericaceae	evergreen shrub
Arctostaphylos regismontana	Kings Mountain manzanita	Ericaceae	perennial evergreen shrub
Astragalus nuttallii var. nuttallii	ocean bluff milk-vetch	Fabaceae	perennial herb
Astragalus pycnostachyus var. pycnostachyus	coastal marsh milk-vetch	Fabaceae	perennial herb
Astragalus tener var. tener	alkali milk-vetch	Fabaceae	annual herb
Atriplex joaquinana	San Joaquin spearscale	Chenopodiaceae	annual herb
Azolla microphylla	Mexican mosquito fern	Azollaceae	annual / perennial herb
Balsamorhiza macrolepis	big-scale balsamroot	Asteraceae	perennial herb
Boechera rubicundula	Mount Day rockcress	Brassicaceae	perennial herb
Calandrinia breweri	Brewer's calandrinia	Montiaceae	annual herb
California macrophylla	round-leaved filaree	Geraniaceae	annual herb
Calochortus umbellatus	Oakland star-tulip	Liliaceae	perennial bulbiferous herb
Calochortus uniflorus	pink star-tulip	Liliaceae	perennial bulbiferous herb
Calyptridium parryi var. hesseae	Santa Cruz Mountains pussypaws	Montiaceae	annual herb
Calystegia collina ssp. venusta	South Coast Range morning-glory	Convolvulaceae	perennial rhizomatous herb
Campanula exigua	chaparral harebell	Campanulaceae	annual herb
Campanula sharsmithiae	Sharsmith's harebell	Campanulaceae	annual herb
Castilleja affinis var. neglecta	Tiburon paintbrush	Orobanchaceae	perennial herb (hemiparasitic)
Castilleja ambigua var. ambigua	johnny-nip	Orobanchaceae	annual herb (hemiparasitic)
Castilleja rubicundula var. rubicundula	pink creamsacs	Orobanchaceae	annual herb (hemiparasitic)
Ceanothus ferrisiae	Coyote ceanothus	Rhamnaceae	perennial evergreen shrub
Centromadia parryi ssp. congdonii	Congdon's tarplant	Asteraceae	annual herb
Centromadia parryi ssp. parryi	pappose tarplant	Asteraceae	annual herb
Chloropyron maritimum ssp. palustre	Point Reyes bird's-beak	Orobanchaceae	annual herb (hemiparasitic)
Chorizanthe cuspidata var. cuspidata	San Francisco Bay spineflower	Polygonaceae	annual herb
Chorizanthe robusta var. robusta	robust spineflower	Polygonaceae	annual herb
Cirsium andrewsii	Franciscan thistle	Asteraceae	perennial herb
Cirsium fontinale var. campylon	Mt. Hamilton fountain thistle	Asteraceae	perennial herb
Cirsium fontinale var. fontinale	Crystal Springs fountain thistle	Asteraceae	perennial herb
Cirsium praeteriens	lost thistle	Asteraceae	perennial herb
Clarkia breweri	Brewer's clarkia	Onagraceae	annual herb
Clarkia concinna ssp. automixa	Santa Clara red ribbons	Onagraceae	annual herb
Collinsia multicolor	San Francisco collinsia	Plantaginaceae	annual herb
Corethrogyne leucophylla	branching beach aster	Asteraceae	perennial herb
Cypripedium fasciculatum	clustered lady's-slipper	Orchidaceae	perennial rhizomatous herb
Cypripedium montanum	mountain lady's-slipper	Orchidaceae	perennial rhizomatous herb
Delphinium californicum ssp. interius	Hospital Canyon larkspur	Ranunculaceae	perennial herb
Dirca occidentalis	western leatherwood	Thymelaeaceae	perennial deciduous shrub
Dudleya abramsii ssp. setchellii	Santa Clara Valley dudleya	Crassulaceae	perennial herb
Elymus californicus	California bottle-brush grass	Poaceae	perennial herb
Equisetum palustre	marsh horsetail	Equisetaceae	perennial rhizomatous herb
Eriastrum tracyi	Tracy's eriastrum	Polemoniaceae	annual herb
Eriogonum argillosum	clay buckwheat	Polygonaceae	annual herb
Eriogonum nudum var. decurrens	Ben Lomond buckwheat	Polygonaceae	perennial herb
Eriogonum umbellatum var. bahiiforme	bay buckwheat	Polygonaceae	perennial herb
Eriophyllum jepsonii	Jepson's woolly sunflower	Asteraceae	perennial herb
Eriophyllum latilobum	San Mateo woolly sunflower	Asteraceae	perennial herb
Eryngium aristulatum var. hooveri	Hoover's button-celery	Apiaceae	annual / perennial herb
Erysimum ammophilum	sand-loving wallflower	Brassicaceae	perennial herb
Erysimum franciscanum	San Francisco wallflower	Brassicaceae	perennial herb
Fissidens pauperculus	minute pocket moss	Fissidentaceae	moss
Fritillaria agrestis	stinkbells	Liliaceae	perennial bulbiferous herb
Fritillaria biflora var. ineziana	Hillsborough chocolate lily	Liliaceae	perennial bulbiferous herb
Fritillaria falcata	talus fritillary	Liliaceae	perennial bulbiferous herb
Fritillaria lanceolata var. tristulis	Marin checker lily	Liliaceae	perennial bulbiferous herb
Fritillaria liliacea	fragrant fritillary	Liliaceae	perennial bulbiferous herb
Galium andrewsii ssp. gatense	phlox-leaf serpentine bedstraw	Rubiaceae	perennial herb
Grimmia torenii	Toren's grimmia	Grimmiaceae	moss
Grindelia hirsutula var. maritima	San Francisco gumplant	Asteraceae	perennial herb
Helianthella castanea	Diablo helianthella	Asteraceae	perennial herb
Helianthus exilis	serpentine sunflower	Asteraceae	annual herb
Hemizonia congesta ssp. congesta	white seaside tarplant	Asteraceae	annual herb
Hesperevax sparsiflora var. brevifolia	short-leaved evax	Asteraceae	annual herb
Hesperocyparis abramsiana var. butanoensis	Butano Ridge cypress	Cupressaceae	perennial evergreen tree
Hesperolinon congestum	Marin western flax	Linaceae	annual herb
Heteranthera dubia	water star-grass	Pontederiaceae	perennial herb
Hoita strobilina	Loma Prieta hoita	Fabaceae	perennial herb
Hordeum intercedens	vernal barley	Poaceae	annual herb
Horkelia cuneata var. sericea	Kellogg's horkelia	Rosaceae	perennial herb
Horkelia marinensis	Point Reyes horkelia	Rosaceae	perennial herb
Hosackia gracilis	harlequin lotus	Fabaceae	perennial rhizomatous herb
Iris longipetala	coast iris	Iridaceae	perennial rhizomatous herb
Isocoma menziesii var. diabolica	Satan's goldenbush	Asteraceae	perennial shrub
Lasthenia californica ssp. macrantha	perennial goldfields	Asteraceae	perennial herb
Lasthenia conjugens	Contra Costa goldfields	Asteraceae	annual herb
Legenere limosa	legenere	Campanulaceae	annual herb
Leptosiphon acicularis	bristly leptosiphon	Polemoniaceae	annual herb
Leptosiphon ambiguus	serpentine leptosiphon	Polemoniaceae	annual herb
Leptosiphon croceus	coast yellow leptosiphon	Polemoniaceae	annual herb
Leptosiphon grandiflorus	large-flowered leptosiphon	Polemoniaceae	annual herb
Leptosiphon rosaceus	rose leptosiphon	Polemoniaceae	annual herb
Leptosyne hamiltonii	Mt. Hamilton coreopsis	Asteraceae	annual herb
Lessingia arachnoidea	Crystal Springs lessingia	Asteraceae	annual herb
Lessingia germanorum	San Francisco lessingia	Asteraceae	annual herb
Lessingia hololeuca	woolly-headed lessingia	Asteraceae	annual herb
Lessingia micradenia var. glabrata	smooth lessingia	Asteraceae	annual herb
Lessingia tenuis	spring lessingia	Asteraceae	annual herb
Lilium maritimum	coast lily	Liliaceae	perennial bulbiferous herb
Limnanthes douglasii ssp. ornduffii	Ornduff's meadofoam	Limnanthaceae	annual herb
Limnanthes douglasii ssp. sulphurea	Point Reyes meadowfoam	Limnanthaceae	annual herb
Lomatium observatorium	Mt. Hamilton lomatium	Apiaceae	perennial herb
Lupinus arboreus var. eximius	San Mateo tree lupine	Fabaceae	perennial evergreen shrub
Madia radiata	showy golden madia	Asteraceae	annual herb
Malacothamnus aboriginum	Indian Valley bush-mallow	Malvaceae	perennial deciduous shrub
Malacothamnus arcuatus	arcuate bush-mallow	Malvaceae	perennial evergreen shrub
Malacothamnus davidsonii	Davidson's bush-mallow	Malvaceae	perennial deciduous shrub
Malacothamnus hallii	Hall's bush-mallow	Malvaceae	perennial evergreen shrub
Malacothrix phaeocarpa	dusky-fruited malacothrix	Asteraceae	annual herb
Meconella oregana	Oregon meconella	Papaveraceae	annual herb
Micropus amphibolus	Mt. Diablo cottonweed	Asteraceae	annual herb
Microseris paludosa	marsh microseris	Asteraceae	perennial herb
Microseris sylvatica	sylvan microseris	Asteraceae	perennial herb
Monardella antonina ssp. antonina	San Antonio Hills monardella	Lamiaceae	perennial rhizomatous herb
Monolopia gracilens	woodland woolythreads	Asteraceae	annual herb
Navarretia cotulifolia	cotula navarretia	Polemoniaceae	annual herb
Navarretia prostrata	prostrate vernal pool navarretia	Polemoniaceae	annual herb
Orthotrichum kellmanii	Kellman's bristle moss	Orthotrichaceae	moss
Pedicularis dudleyi	Dudley's lousewort	Orobanchaceae	perennial herb
Penstemon rattanii var. kleei	Santa Cruz Mountains beardtongue	Plantaginaceae	perennial herb
Pentachaeta bellidiflora	white-rayed pentachaeta	Asteraceae	annual herb
Pentachaeta exilis ssp. aeolica	San Benito pentachaeta	Asteraceae	annual herb
Perideridia gairdneri ssp. gairdneri	Gairdner's yampah	Apiaceae	perennial herb
Phacelia phacelioides	Mt. Diablo phacelia	Boraginaceae	annual herb
Pinus radiata	Monterey pine	Pinaceae	perennial evergreen tree
Piperia candida	white-flowered rein orchid	Orchidaceae	perennial herb
Piperia leptopetala	narrow-petaled rein orchid	Orchidaceae	perennial herb
Piperia michaelii	Michael's rein orchid	Orchidaceae	perennial herb
Plagiobothrys chorisianus var. chorisianus	Choris' popcorn-flower	Boraginaceae	annual herb
Plagiobothrys chorisianus var. hickmanii	Hickman's popcorn-flower	Boraginaceae	annual herb
Plagiobothrys diffusus	San Francisco popcorn-flower	Boraginaceae	annual herb
Plagiobothrys glaber	hairless popcorn-flower	Boraginaceae	annual herb
Plagiobothrys uncinatus	hooked popcorn-flower	Boraginaceae	annual herb
Plagiobothrys verrucosus	warty popcorn-flower	Boraginaceae	annual herb
Polemonium carneum	Oregon polemonium	Polemoniaceae	perennial herb
Potentilla hickmanii	Hickman's cinquefoil	Rosaceae	perennial herb
Psilocarphus brevissimus var. multiflorus	Delta woolly-marbles	Asteraceae	annual herb
Ranunculus lobbii	Lobb's aquatic buttercup	Ranunculaceae	annual herb
Sanicula hoffmannii	Hoffmann's sanicle	Apiaceae	perennial herb
Sanicula saxatilis	rock sanicle	Apiaceae	perennial herb
Senecio aphanactis	chaparral ragwort	Asteraceae	annual herb
Sidalcea malachroides	maple-leaved checkerbloom	Malvaceae	perennial herb
Silene verecunda ssp. verecunda	San Francisco campion	Caryophyllaceae	perennial herb
Stebbinsoseris decipiens	Santa Cruz microseris	Asteraceae	annual herb
Streptanthus albidus ssp. albidus	Metcalf Canyon jewel-flower	Brassicaceae	annual herb
Streptanthus albidus ssp. peramoenus	most beautiful jewel-flower	Brassicaceae	annual herb
Streptanthus callistus	Mt. Hamilton jewel-flower	Brassicaceae	annual herb
Stuckenia filiformis ssp. alpina	slender-leaved pondweed	Potamogetonaceae	perennial rhizomatous herb
Suaeda californica	California seablite	Chenopodiaceae	perennial evergreen shrub
Toxicoscordion fontanum	marsh zigadenus	Melanthiaceae	perennial bulbiferous herb
Trifolium amoenum	two-fork clover	Fabaceae	annual herb
Trifolium hydrophilum	saline clover	Fabaceae	annual herb
Triphysaria floribunda	San Francisco owl's-clover	Orobanchaceae	annual herb
Triquetrella californica	coastal triquetrella	Pottiaceae	moss
Tropidocarpum capparideum	caper-fruited tropidocarpum	Brassicaceae	annual herb
Usnea longissima	Methuselah's beard lichen	Parmeliaceae	fruticose lichen (epiphytic)

Full length version of an article published in the May-June 2017 Blazing Star Newsletter

By Elan Alford, Rare Plants Chair, San Mateo County - April 12, 2017

Where are rare plants found in the Santa Clara Valley chapter? What is different about different parts of the chapter service area? Think about where you may live, or work. Do you know where a rare plant hotspot is near you? Have you been to any of these places and seen the rare plants in their habitats?

There is a state level CNPS effort underway to identify conservation priority areas. The program is covered in the 2015-2016 Conservation Report, available from the CNPS website. The state level program is called the IPA Initiative. IPA stands for “Important Plant Areas”. The goal is to create a statewide database and comprehensive map of the most important plant conservation targets. It seems that the idea germinated at the state level after the East Bay Chapter produced their guidebook, Guidebook to the Botanical Priority Protection Areas by Heath Bartosh, Lech Naumovich, and Laura Baker.

Read more …

Seven rare serpentine plants of San Mateo and Santa Clara Counties receive federal protection

The Blazing Star, March/April 1995

Seven rare serpentine plants of San Mateo and Santa Clara Counties receive federal protection Serpentine-rich soils have long been known in our area to provide some of the best spring color displays. This is because the Mediteranean annual grasses cannot tolerate the low calcium and high magnesium of serpentine soils and therefore don't compete with the native annuals that were once so plentiful in our state. Unfortunately, we have been losing these serpentine grasslands to housing, highways and other development, with the result that we have endangered some rare species, some of which now exist only in one location.

While the state passed legislation two years ago to protect these species, the federal government has added their protection as of early this month. While the listings impose few direct restrictions on private land owners, they provide much tougher protection for the plants on public land, or on private lands where acitvities require federal permits.

Included in the listing are the Santa Clara Valley dudleya (Dudleya setchellii), Metcalf canyon jewelflower (Streptanthus albidus ssp. albidus), Coyote ceanothus (Ceanothus ferrisae), all from Santa Clara County; and the fountain thistle (Cirsium fontinale var. fontinale), San Mateo woolly sunflower (Eriophyllum latilobum), white-rayed pentachaeta (Pentachaeta bellidiflora), and the Marin western flax (Hesperolinon congestum), all from San Mateo County. In addition one plant from San Francisco was listed (the Clarkia franciscana), and two from Marin, the Tiburon jewelflower and Pennell's birdbeak.

Thanks to the Rare plant committee for their earlier work on these species, and particularly to members Toni Corelli, Zoe Chandik, and Sara Timby for petitioning for their protection.

The Blazing StarMay/June 2014

By Justen Whittall

On Sunday, March 2nd, 2014, the federally-endangered Metcalf Canyon Jewelflower (Streptanthus albidus ssp. albidus) was reintroduced to Tulare Hill in southern Santa Clara County. Approximately 16,000 seeds were sown in four locations on Tulare Hill, an isolated serpentine grassland nestled between Santa Teresa Blvd. and Monterey Hwy. The property is owned by Santa Clara County Parks and the Silicon Valley Land Conservancy who are partners in the reintroduction. Seeds will also be planted near existing populations at the Motorcycle County Park atop Metcalf Rd. on March 4th, 2014 as controls and to supplement those existing populations.

This historic population of jewelflower at Tulare Hill declined primarily due to overgrazing by cattle. No jewelflowers have persisted at Tulare Hill since 1980 when the remaining population was extirpated by residential development.

A modified grazing regime and improved understanding of the jewelflower’s biology have been a collaborative effort ...

Read more (PDF).