While great progress has been made in our understanding of the flora of California, new findings occur every year as a result of novel species findings, the application of new research methods to 'old' plants, or range extensions of plants that also occur outside of California. Join us to discuss exciting new findings.
SESSION CHAIRS Adam Searcy1, Nina House2
1California Native Plant Society, Sacramento, CA, United States. 2University and Jepson Herbaria, Berkeley, CA, United States
Adam Searcy
California Native Plant Society
Adam Searcy is the current California Native Plant Society Rare Plant Botanist. He earned a B.S. in Ecology & Evolutionary Biology from U.C. Santa Cruz (‘09). Adam's career experience includes non-profit work and biological consulting. He has worked on a variety of projects involving special status plant and animal species at field sites on National Forests, military bases, and eight of California’s offshore islands (he has yet to find work on Catalina). Adam is passionate about biodiversity, conservation, and community science. In his free time, he enjoys birding, botanizing, iNatting, and reading.
Nina House
University and Jepson Herbaria
Nina House is the Managing Editor of the Jepson eFlora and a co-coordinator of the Jepson Public Programs at the University & Jepson Herbaria. She obtained a Master's Degree in Botany from California Botanic Garden. Her thesis was a vascular flora of the Manter and Salmon Creek watersheds, located in Tulare County, California.
25.1 Molecules and Morphology Support the Recognition of a New, Rare Fringepod (Thysanocarpus; Brassicaceae) Endemic to the Santa Monica Mountains
C. Matt Guilliams1, Kai Pessanha1,2, John Knapp3, Kristen Hasenstab-Lehman1
1Santa Barbara Botanic Garden, Santa Barbara, CA, United States. 2Santa Barbara City College, Santa Barbara, CA, United States. 3Catalina Island Conservancy, Avalon, CA, United States
Description Thysanocarpus conchuliferus Greene is a diminutive annual herb in the Brassicaceae, or mustard family. Known as the Santa Cruz Island fringepod, the species was thought to be limited to a global distribution of only 15 Element Occurrences on Santa Cruz Island (SCR), California. Due to rarity and habitat impacts, the species was listed as Endangered under the Endangered Species Act and given a CNPS ranking of 1B.2. In 2008, plants resembling T. conchuliferus were collected in the Santa Monica Mountains (SMM), northwest of Los Angeles. Since that time, additional SMM populations have been documented, calling into question the circumscription and distribution of this Endangered species. Here we use phylogenomics and morphometrics to evaluate the circumscription of T. conchuliferus and assess the relationship between plants from SCR and the SMM. The genomic analyses included 93 samples of Thysanocarpus. Samples from the SMM form a strongly supported evolutionary group distinct from T. conchuliferus of SCR. The morphometric analysis included 72 individuals of T. conchuliferus, 22 from SCR and 50 from the SMM. We measured eight characters, and plants from SCR and SMM were strongly statistically different in four of them. Therefore, it appears that the plants from the SMM are genetically and morphologically distinct from T. conchuliferus from SCR and other members of the genus and likely warrant taxonomic recognition. Excitingly, this new taxon would be an SMM narrow endemic, awaiting detection in a relatively small mountain range surrounded by the second largest metro area in the United States.
Presenter Bios
C. Matt Guilliams
Santa Barbara Botanic Garden
Matt is the Ken and Shirley Tucker plant systematist and curator of the Clifton Smith Herbarium at Santa Barbara Botanic Garden. As a botanist/plant systematist, his overall focus is the study of the flora of California, which includes floristics, biodiversity description, inferring evolutionary patterns, and conservation genetics of rare plants. Matt earned his bachelor’s and master’s degrees in evolutionary biology from San Diego State University and his doctorate in integrative biology from University of California, Berkeley. He has been working as a botanist in the state since 1998.
25.2 Flora of the San Jacinto and Santa Rosa Mountains: Selected Highlights
Scott D. White
Aspen Environmental Group, Upland, CA, United States. California Botanic Garden, Claremont, CA, United States
Description The San Jacinto and Santa Rosa mountains are sky islands at the northern end of the Peninsular Ranges. They separate the California Floristic Province from the Sonoran Desert. From west to east, they support chaparral and montane and subalpine forests, then transition steeply downslope to desert shrublands. Localized wetlands and edaphic habitats are scattered throughout. The highest peak, Mt. San Jacinto, rises to 10,800 feet. The Flora of the San Jacintos was first documented by H. M. Hall, at the turn of the 20th century. My field work and data compilation build upon Hall’s work by expanding the geographic range and incorporating decades of subsequent specimen data and recent photographic documentation by citizen scientists. This talk focuses on a few edaphic or elevational island-like locations and their disjunct taxa that warrant further exploration, monitoring, or deeper systematic research:
(1) Carbonate substrates: Long-distance disjunct occurrences of Eriogonum microtheca and Abronia nana. (2) Pleistocene alluvial quartzite and schist: Long-distance disjunct occurrences of Artemisia aff. arbuscula and Portulaca halimoides; also supports Boechera johnstonii (CRPR 1B). (3) Seasonal wetlands around Garner Valley and Vandeventer Flats: Marsilea vestita, Atriplex parishii, Myosurus minimus, Castilleja densiflora, and C. attenuata. (4) Montane meadows: Apparently extirpated occurrences of Castilleja lasiorhyncha, and Malaxis brachypoda and at-risk extant occurrences of Limnanthes alba subsp. parishii, Spiranthes sp. and others. (5) High elevation snowmelt habitats: Possibly extirpated occurrences of at least two taxa documented by Hall ca. 1900 (Oxyria digyna and Ranunculus eschscholtzii) and several at-risk extant taxa.
Presenter Bios
Scott D. White
Aspen Environmental Group
Scott White recently retired from a long career as a consulting biologist. He holds both a BA and an MA degree from Humboldt State University (now Cal Poly Humboldt). Scott is a former President of the Southern California Botanists and former co-editor of the journal Crossosoma. He is a co-author of The Vascular Plants of Western Riverside County and a Research Associate at Rancho Santa Ana Botanic Garden. He was an original member of the CNPS Vegetation Committee. He has been conducting floristic surveys throughout southern California since 1987. In retirement, he is focusing on his favorite long-term project, a vouchered flora of the San Jacinto Mountains, based on herbarium specimens and his own collections.
25.3Ephedra in Kern County Includes Two Additional Species New to the California Flora
Dr. Richard W. Spjut
World Botanical Associates, Bakersfield, CA, United States. CNPS Kern Chapter, Bakersfield, CA, United States
Description The Jepson Manual reports three of the six native California species of Ephedra in Kern County: E. californica, E. nevadensis, and E. viridis. However, in conducting field work for preparation of a manual on the trees and shrubs of Kern County, it became necessary to study Ephedra taxonomic literature and images of herbarium specimens including types throughout the range of the genus. Additional species are apparent by differences in perennial growth patterns (such as rhizomatous branching, development of woody trunk), stem color, and seasonal development of leaves with or without cones. Examples of these differences will be shown. New geographical occurrences are reported for two species not previously known in California, a nonnative Mediterranean species, E. foliata, and a putative hybrid of two native southwestern U.S. species (E. × arenicola), here regarded E. arenicola. Specimens of both species were collected in the Piute Mountains—E. foliata was found on talus near the base of a rock face on the west-facing slope of Erskine Creek in May 2012, with immature cones, and has not been observed there since; E. arenicola was collected on a northeast-facing open slope in Squirrel Canyon in April 2014, appearing relatively rare and closely associated with a monoecious Ephedra sp., both possibly extirpated by the 2016 Erskine Fire. Herbarium specimens currently in the private World Botanical Associates herbarium are scheduled to be transferred to California Academy of Sciences.
Presenter Bios
Dr. Richard W. Spjut
World Botanical Associates
Dr. Spjut has extensive field experience in collecting and identifying plants in East Africa, Western Australia, and southwestern North America. He has published taxonomic revisions of the conifer genus Taxus and the lichen genus Niebla, describing many new species in both genera. His presentation on Ephedra relates to preparing a manual of the trees and shrubs of Kern County.
25.4 Revealing Hidden Diversity: New Findings in the Flora of San Diego County
Dr. Jon P. Rebman1, Dr. Michael G. Simpson2
1San Diego Natural History Museum, San Diego, CA, United States. 2San Diego State University, San Diego, CA, United States
Description The newly published Checklist of the Vascular Plants of San Diego County (Rebman, Gregory, and Simpson, 2025) documents more than 249 new plant records for the region, bringing the county’s flora to an impressive 2,873 total taxa (2,645 species) representing 960 genera and 171 families. These additions include 88 native and 157 non-native naturalized taxa. Notably, several of the native records are new for the United States or Southern California, while others are species newly described to science in recent years. Many discoveries stem from community-science contributions via iNaturalist and from targeted surveys in San Diego’s urban canyons as part of the multidisciplinary Healthy Canyons Initiative. The results highlight the dynamic and ever-expanding nature of San Diego County’s flora—one that still holds unnamed species awaiting formal description.
Presenter Bios
Dr. Jon P. Rebman
San Diego Natural History Museum
Jon P. Rebman, Ph.D., has been exploring and documenting the plants of southern California and Baja California for over three decades. As the Mary and Dallas Clark Endowed Chair and Curator of Botany at the San Diego Natural History Museum, he specializes in cacti—especially chollas and prickly-pears—while also leading broad floristic research across the region. Dr. Rebman has co-authored definitive plant checklists for San Diego County and Baja California, described 33 plants new to science, and collected more than 37,200 specimens. His passion for fieldwork, taxonomy, and conservation continues to deepen understanding of the region’s remarkable botanical diversity.
25.5 Tecopa Bird's Beak and Beyond: Genetic and Ecological Research Reveal Two New Species of Chloropyron (Orobanchaceae) Native to the Great Basin and Mojave Deserts in California and Nevada
Naomi Fraga, Erica Fontanez, Peri Lee Pipkin
California Botanic Garden, Claremont, CA, United States
Description Chloropyron tecopense (Tecopa bird’s beak) is a rare, hemiparasitic annual herb in the Orobanchaceae that is restricted to alkali wetlands in the transition zone between the Great Basin and Mojave deserts in Inyo and San Bernardino counties in California, and Esmeralda and Nye counties in Nevada. It was first described in 1950 from material collected in 1949 in Tecopa Hot Springs, Inyo County, California, although the first voucher collection was made in 1888 by William H. Shockley at Gap Spring, Esmeralda County, Nevada. Major threats include hydrological alteration, groundwater depletion, mining exploration, geothermal exploration, proposed industrial solar projects, off highway vehicle incursion, browsing and trampling by feral horses and cattle, and climate change. We collected and analyzed genetic, morphological and ecological data, to evaluate the conservation and taxonomic status of C. tecopense across its range. Our study finds that C. tecopense is strongly supported as a single lineage in a phylogenetic analysis, with strong genetic differentiation between three isolated occurrence locations (Fish Lake Valley, Ash Meadows, Shoshone/Tecopa). These three occurrences are also differentiated by phenology, morphology, and their ecological requirements, providing evidence for the recognition of two new taxa native to the Mojave and Great Basin deserts. A fourth historical occurrence in Death Valley National Park is presumed extirpated, possibly due to climate change or hydrological alteration. This presentation will provide an overview of recent findings that contribute to our understanding of rare habitat specialists.
Presenter Bios
Naomi Fraga
California Botanic Garden
Naomi Fraga is Director of Conservation Programs at California Botanic Garden in Claremont, CA. Her research interests include plant geography, conservation biology, rare plants of western North America, and taxonomy of monkeyflowers (Phrymaceae). Naomi hold a Ph.D. in Botany from Claremont Graduate University. In 2023, she received the Peter Raven Award from the American Society of Plant Taxonomists. In 2021 she was awarded the Center for Biological Diversity E.O. Wilson Award for Outstanding Science in Biodiversity Conservation and the Center for Plant Conservation Star Award. Naomi serves on the board of the Southern California Botanists, Treasurer for the Amargosa Conservancy, and is chair of the Public Policy Committee of the Botanical Society of America.
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The mission of the California Native Plant Society is to protect California’s native plants and their natural habitats, today and into the future, through science, education, stewardship, gardening, and advocacy.
DateSaturday, February 7
