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California Native Plant Society

Santa Clara Valley Chapter

Rare & Endangered Plants

Rare Plant Program

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.). 

Santa Clara Valley Chapter Rare Plant List and Plant Pages

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 duttonii
Acanthomintha lanceolata Santa Clara thorn-mint Lamiaceae annual herb  
Agrostis blasdalei Blasdale's bent grass Poaceae perennial rhizomatous herb Agrostis blasdalei
Allium peninsulare var. franciscanum Franciscan onion Alliaceae perennial bulbiferous herb Allium peninsulare var. franciscanum
Allium sharsmithiae Sharsmith's onion Alliaceae perennial bulbiferous herb  
Amsinckia lunaris bent-flowered fiddleneck Boraginaceae annual herb Amsinckia lunaris
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 andersonii
Arctostaphylos imbricata San Bruno Mountain manzanita Ericaceae perennial evergreen shrub Arctostaphylos imbricata
Arctostaphylos montaraensis Montara manzanita Ericaceae perennial evergreen shrub Arctostaphylos montaraensis
Arctostaphylos pacifica Pacific manzanita Ericaceae evergreen shrub Arctostaphylos pacifica
Arctostaphylos regismontana Kings Mountain manzanita Ericaceae perennial evergreen shrub Arctostaphylos regismontana
Astragalus nuttallii var. nuttallii ocean bluff milk-vetch Fabaceae perennial herb  
Astragalus pycnostachyus var. pycnostachyus coastal marsh milk-vetch Fabaceae perennial herb Astragalus pycnostachyus var. pycnostachyus
Astragalus tener var. tener alkali milk-vetch Fabaceae annual herb Astragalus tener var. tener
Atriplex joaquinana San Joaquin spearscale Chenopodiaceae annual herb Atriplex joaquinana
Azolla microphylla Mexican mosquito fern Azollaceae annual / perennial herb  
Balsamorhiza macrolepis big-scale balsamroot Asteraceae perennial herb Balsamorhiza macrolepis
Boechera rubicundula Mount Day rockcress Brassicaceae perennial herb  
Calandrinia breweri Brewer's calandrinia Montiaceae annual herb  
California macrophylla round-leaved filaree Geraniaceae annual herb California macrophylla
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 exigua
Campanula sharsmithiae Sharsmith's harebell Campanulaceae annual herb Campanula sharsmithiae
Castilleja affinis var. neglecta Tiburon paintbrush Orobanchaceae perennial herb (hemiparasitic) Castilleja affinis var. neglecta
Castilleja ambigua var. ambigua johnny-nip Orobanchaceae annual herb (hemiparasitic)  
Castilleja rubicundula var. rubicundula pink creamsacs Orobanchaceae annual herb (hemiparasitic) Castilleja rubicundula var. rubicundula
Ceanothus ferrisiae Coyote ceanothus Rhamnaceae perennial evergreen shrub Ceanothus ferrisiae
Centromadia parryi ssp. congdonii Congdon's tarplant Asteraceae annual herb Centromadia parryi ssp. congdonii
Centromadia parryi ssp. parryi pappose tarplant Asteraceae annual herb Centromadia parryi ssp. parryi
Chloropyron maritimum ssp. palustre Point Reyes bird's-beak Orobanchaceae annual herb (hemiparasitic) Chloropyron maritimum ssp. palustre
Chorizanthe cuspidata var. cuspidata San Francisco Bay spineflower Polygonaceae annual herb Chorizanthe cuspidata var. cuspidata
Chorizanthe robusta var. robusta robust spineflower Polygonaceae annual herb Chorizanthe robusta var. robusta
Cirsium andrewsii Franciscan thistle Asteraceae perennial herb  
Cirsium fontinale var. campylon Mt. Hamilton fountain thistle Asteraceae perennial herb Cirsium fontinale var. campylon
Cirsium fontinale var. fontinale Crystal Springs fountain thistle Asteraceae perennial herb Cirsium fontinale var. fontinale
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 Dudleya abramsii ssp. setchellii
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 nudum var. decurrens
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 Eriophyllum latilobum
Eryngium aristulatum var. hooveri Hoover's button-celery Apiaceae annual / perennial herb Eryngium aristulatum var. hooveri
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 biflora var. ineziana
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 Hesperolinon congestum
Heteranthera dubia water star-grass Pontederiaceae perennial herb  
Hoita strobilina Loma Prieta hoita Fabaceae perennial herb Hoita strobilina
Hordeum intercedens vernal barley Poaceae annual herb  
Horkelia cuneata var. sericea Kellogg's horkelia Rosaceae perennial herb Horkelia cuneata var. sericea
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 californica ssp. macrantha
Lasthenia conjugens Contra Costa goldfields Asteraceae annual herb Lasthenia conjugens
Legenere limosa legenere Campanulaceae annual herb Legenere limosa
Leptosiphon acicularis bristly leptosiphon Polemoniaceae annual herb  
Leptosiphon ambiguus serpentine leptosiphon Polemoniaceae annual herb  
Leptosiphon croceus coast yellow leptosiphon Polemoniaceae annual herb Leptosiphon croceus
Leptosiphon grandiflorus large-flowered leptosiphon Polemoniaceae annual herb  
Leptosiphon rosaceus rose leptosiphon Polemoniaceae annual herb Leptosiphon rosaceus
Leptosyne hamiltonii Mt. Hamilton coreopsis Asteraceae annual herb Leptosyne hamiltonii
Lessingia arachnoidea Crystal Springs lessingia Asteraceae annual herb Lessingia arachnoidea
Lessingia germanorum San Francisco lessingia Asteraceae annual herb  
Lessingia hololeuca woolly-headed lessingia Asteraceae annual herb Lessingia hololeuca
Lessingia micradenia var. glabrata smooth lessingia Asteraceae annual herb Lessingia micradenia var. glabrata
Lessingia tenuis spring lessingia Asteraceae annual herb  
Lilium maritimum coast lily Liliaceae perennial bulbiferous herb Lilium maritimum
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 Lomatium observatorium
Lupinus arboreus var. eximius San Mateo tree lupine Fabaceae perennial evergreen shrub  
Madia radiata showy golden madia Asteraceae annual herb Madia radiata
Malacothamnus aboriginum Indian Valley bush-mallow Malvaceae perennial deciduous shrub Malacothamnus aboriginum
Malacothamnus arcuatus arcuate bush-mallow Malvaceae perennial evergreen shrub Malacothamnus arcuatus
Malacothamnus davidsonii Davidson's bush-mallow Malvaceae perennial deciduous shrub Malacothamnus davidsonii
Malacothamnus hallii Hall's bush-mallow Malvaceae perennial evergreen shrub Malacothamnus hallii
Malacothrix phaeocarpa dusky-fruited malacothrix Asteraceae annual herb  
Meconella oregana Oregon meconella Papaveraceae annual herb Meconella oregana
Micropus amphibolus Mt. Diablo cottonweed Asteraceae annual herb  
Microseris paludosa marsh microseris Asteraceae perennial herb Microseris paludosa
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 Monolopia gracilens
Navarretia cotulifolia cotula navarretia Polemoniaceae annual herb  
Navarretia prostrata prostrate vernal pool navarretia Polemoniaceae annual herb Navarretia prostrata
Orthotrichum kellmanii Kellman's bristle moss Orthotrichaceae moss  
Pedicularis dudleyi Dudley's lousewort Orobanchaceae perennial herb Pedicularis dudleyi
Penstemon rattanii var. kleei Santa Cruz Mountains beardtongue Plantaginaceae perennial herb Penstemon rattanii var. kleei
Pentachaeta bellidiflora white-rayed pentachaeta Asteraceae annual herb Pentachaeta bellidiflora
Pentachaeta exilis ssp. aeolica San Benito pentachaeta Asteraceae annual herb Pentachaeta exilis ssp. aeolica
Perideridia gairdneri ssp. gairdneri Gairdner's yampah Apiaceae perennial herb  
Phacelia phacelioides Mt. Diablo phacelia Boraginaceae annual herb Phacelia phacelioides
Pinus radiata Monterey pine Pinaceae perennial evergreen tree Pinus radiata
Piperia candida white-flowered rein orchid Orchidaceae perennial herb Piperia candida
Piperia leptopetala narrow-petaled rein orchid Orchidaceae perennial herb Piperia leptopetala
Piperia michaelii Michael's rein orchid Orchidaceae perennial herb Piperia michaelii
Plagiobothrys chorisianus var. chorisianus Choris' popcorn-flower Boraginaceae annual herb Plagiobothrys chorisianus var. chorisianus
Plagiobothrys chorisianus var. hickmanii Hickman's popcorn-flower Boraginaceae annual herb Plagiobothrys chorisianus var. hickmanii
Plagiobothrys diffusus San Francisco popcorn-flower Boraginaceae annual herb Plagiobothrys diffusus
Plagiobothrys glaber hairless popcorn-flower Boraginaceae annual herb Plagiobothrys glaber
Plagiobothrys uncinatus hooked popcorn-flower Boraginaceae annual herb Plagiobothrys uncinatus
Plagiobothrys verrucosus warty popcorn-flower Boraginaceae annual herb  
Polemonium carneum Oregon polemonium Polemoniaceae perennial herb  
Potentilla hickmanii Hickman's cinquefoil Rosaceae perennial herb Potentilla hickmanii
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 Sanicula saxatilis
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 Silene verecunda ssp. verecunda
Stebbinsoseris decipiens Santa Cruz microseris Asteraceae annual herb Stebbinsoseris decipiens
Streptanthus albidus ssp. albidus Metcalf Canyon jewel-flower Brassicaceae annual herb Streptanthus albidus ssp. albidus
Streptanthus albidus ssp. peramoenus most beautiful jewel-flower Brassicaceae annual herb Streptanthus albidus ssp. peramoenus
Streptanthus callistus Mt. Hamilton jewel-flower Brassicaceae annual herb Streptanthus callistus
Stuckenia filiformis ssp. alpina slender-leaved pondweed Potamogetonaceae perennial rhizomatous herb  
Suaeda californica California seablite Chenopodiaceae perennial evergreen shrub Suaeda californica
Toxicoscordion fontanum marsh zigadenus Melanthiaceae perennial bulbiferous herb  
Trifolium amoenum two-fork clover Fabaceae annual herb Trifolium amoenum
Trifolium hydrophilum saline clover Fabaceae annual herb Trifolium hydrophilum
Triphysaria floribunda San Francisco owl's-clover Orobanchaceae annual herb Triphysaria floribunda
Triquetrella californica coastal triquetrella Pottiaceae moss  
Tropidocarpum capparideum caper-fruited tropidocarpum Brassicaceae annual herb Tropidocarpum capparideum
Usnea longissima Methuselah's beard lichen Parmeliaceae fruticose lichen (epiphytic)  

Rare Plant Hotspots in San Mateo and Santa Clara Counties

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?

map showing santa clara county rare plant hotspots

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 ...

Rare Serpentine Plants Receive Federal Protection

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.

Dudleya setchellii at Coyote RidgeIncluded 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.

Jewelflower Returns to Tulare Hill

hand holding seed packetThe 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).

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