California Botanical Society

Paul Silva in 1954 in Collioure, France




Paul Silva Student Research Grants

The Paul Silva Student Research Grant is named after Paul Silva (1922-2014), a phycologist and Curator of Algae at the University Herbarium, UC Berkeley, whose bequest to the Society has made this award possible. Awards are made to qualified undergraduate and graduate student members of the Society working on projects that will help achieve the Society's goal of advancing Western American botany. Students from any accredited university doing botanical research within western North America and who are members of the Society are eligible for this award.

The next deadline for receipt of applications for a Paul Silva Student Research Grant is May 15, 2019. Proposals will be reviewed by a panel of experts, and winners will be announced within two months of the application deadline.

For application details and application form are here:

Application Details

Application Form

2018 Recipients

Nicole Kollars - University of California, Davis

The consequences of grazing disturbance on the genetic diversity of seagrass:

Zostera marina is a native species of seagrass found in harbors and bays along the coast of California. Zostera meadows are essential winter habitats for Pacific Brant geese who consume seagrass leaves to fuel their return migration to the Arctic and to support summer breeding. Previous research has shown that the genetic diversity (the number of unique clones) of seagrass is important in helping the seagrass population recover from the biomass removal caused by grazing. However, we do not know how the act of grazing affects the genetic diversity of seagrass. Does grazing reduce, maintain, or enhance genetic diversity? To address this question, I am conducting a field experiment in Bodega Harbor, CA that manipulates how often the seagrass is grazed and measures how differences in this grazing intensity affect the number of unique clones. Because the genetic diversity of seagrass is important to its persistence, understanding the direct effects of geese on seagrass genetic diversity is essential to understanding how changes in grazing intensity will affect the long-term sustainability of seagrass populations.

Audrey Haynes, University of California, Berkeley

Night-time transpiration in parasitic plants:

It’s generally assumed that plants do not transpire at night because stomata close in the dark. For non-CAM plants, darkness halts crucial aspects of photosynthesis and consequently stomatal closure limits water loss when there is no carbon to be gained. However, nocturnal transpiration has been observed across many taxa and ecosystems, a phenomenon which remains poorly understood. Parasitic plants may aid our understanding of this process because they are theoretically released from two of the major drivers of stomatal closure at night: the inability to gain carbon in darkness and the need to conserve water. In theory this unique water-carbon trade-off should lead to nocturnal transpiration in parasitic plants. Indeed, nocturnal transpiration has been observed in some parasitic plants but it has never been investigated directly nor at a broad scale. Understanding whether or not parasitic plants engage in nocturnal transpiration and would enhance our understanding of this understudied, yet important group of plants. In addition, this work will help illuminate possible explanations for nocturnal transpiration among all plants. My project investigates patterns of transpiration among parasitic plants through a general survey of California parasitic plants, the first broad survey of nocturnal transpiration in this group. I expect that parasitic plants’ nocturnal transpiration will significantly exceed their neighbors and may be particularly high in wetter and/or low nutrient environments. In addition, I expect that obligate parasites will have higher rates of nocturnal transpiration than hemi-parasites.

Emily Cox, University of California, Berkeley

Lasthenia californica and water stress: A glimpse into the future of California grasslands:

Climate change impacts the severity and frequency of droughts in California. As a result, native plants will likely face changes in soil moisture as temperature and weather patterns shift. Lasthenia californica, commonly known as California goldfields, is a species of native California flower with habitats ranging from northern to southern California. Therefore, this species is ideal for testing how a controlled variable affects a set of populations differing by latitude. Through a gridded greenhouse experiment, I will measure the effects of water stress on the growth rate and flower count of this species of native California daisy to explore if there is variation in response between northern and southern populations. I will also measure general survivorship, days to germination, and days to flowering to further compare responses among the geographically distinct populations. The results of my research are expected to show that individuals from southern populations will be more resilient to drought conditions, by exhibiting slower growth rates and higher flower counts than plants from northern populations exposed to the same degree of water stress. This higher drought fitness is expected to significantly correlate with higher numbers of flowers, a measure of reproductive fitness. Studying the effects of limited water availability on growth and reproductive ability of specific native California plants can provide insights into how climate change will impact important California ecosystems such as grasslands. This knowledge of ecological vulnerability is crucial when assessing and weighing the importance of mitigating the many detrimental effects of climate change.


2018 - Nicole Kollars - University of California, Davis: The consequences of grazing disturbance on the genetic diversity of seagrass

2018 - Audrey Haynes, University of California, Berkeley: Night-time transpiration in parasitic plants

2018 - Emily Cox, University of California, Berkeley: Lasthenia californica and water stress: A glimpse into the future of California grasslands

2017 - Jennifer Harrower, University of California, Santa Cruz: Investigating the impacts of climate change on Joshua trees and their symbionts

2017 - Nila Le, University of San Francisco: Climate change and limited distribution of the California native plant and rocky outcrop endemic Arabis blepharophylla

2017 - Annie Ayers, Kate Miller, Drew Burke & Maxwell McCollum, California Polytechnic University, San Luis Obispo: A floristic survey of Mt. Conness and Skelton Plateau in Yosemite National Park

2016 - Kristen Peach, University of California, Santa Barbara: Predicting responses of wild plant populations to climate change: Integrating climatic and biological factors influencing the ecology of floral attraction

annettacarter1932 Annetta Carter in 1932 on the Calypso Club trip to Ft. Bragg

Photo: Debra Valov

Annetta Carter Memorial Fund Grants

The Annetta Carter Memorial Fund honors Annetta Carter, who devoted the last 40 years of her life to the study of the Baja California flora. Her special interests were floristics, history, biogeography, and ethnobotany of the Sierra de la Giganta.

The review committee will consider proposals from members of the California Botanical Society who are conducting or proposing to conduct botanical research on the green plants of Baja California. Studies of populations outside Baja will also be considered if they elucidate problems in Baja California.

Application details are here:

- In English

- En Español

Next deadline is December 31, 2019


2018 - Isaac H.L. Marck: Revising the Systematics of Amauria, the Baja California endemic rock daisies

2018 - Benjamin T. Wilder: Botanical Diversity and Change of Volcan Tres Virgenes

2016 - Andy Siekkinen: Searching for Hechtia gayorum, the Baja Endemic Bromeliad

2014 - C. Matt Guilliams: Distribution, extent, and floristics of vernal pools in Baja California, Mexico

2014 - Daniel E. Winkler: Reconnaissance of the status of a rare, endemic plant species in Sierra de San Pedro Mártir National Park, Baja California, Mexico

2012 - Kristen Hasenstab-Lehman: The vascular flora of Greater San Quintin, Baja California, Mexico

2010 - Christopher DiVittorio: Adaptive radiation of Encelia (Asteraceae) in Baja California

2008 - Sula Vanderplank: The vascular flora of Greater San Quintin, Baja California, Mexico

2006 - Peter J. Garcia: Plant collecting on Isla Angel, Sea of Cortez

2005 - Jon P. Rebman: Checklist of the plants of Lower California, Mexico

IMG_7113 Justen Whittall, Madroño Editor, with Arjun (left) and Ayana (right)

CBS award winners.Santa Cruz Justen Whittall with (starting from left) Ashlyn, Caitlin and Emma

California Botanical Society
Student Science Fair Prizes

The Society awards prizes from time to time to middle and high school student scientists for botanical projects presented at recognized California science fairs. The program was initiated in 2018 and is aimed to encourage our next generation of botanists.


2018 Synopsys Championship (Santa Clara County, California)

  • Anaya Subramanian, Los Altos High School, Los Altos, CA: Enhancement of mitochondrial function and seed germination by pterostilbene, ellagic acid and nicotinamide riboside (1st place High School division)
  • Alexander Michael Noriega, Oak Grove High School, San Jose, CA: Antimicrobial Synergies of the Digestive Juices Formed by Nepenthaceae Plants (2nd place High School division)
  • Ayana Rose Wilmot, Oakwood School, Morgan Hill, CA: Factors Affecting the Rate of Photosynthesis of California Lichens (1st place Middle School division)
  • Arjun Rajaram, Challenger School-Almaden, San Jose, CA: The effect of different plants on firescaping (2nd place Middle School division)

2018 Santa Cruz County Science & Engineering Fair

  • Emma Schaefer-Whittall, Scotts Valley High School, Scotts Valley, CA: Alkaloid Quantification of Catharanthus roseus and Vinca major and its Effects on Cell Viability (1st place High School division)
  • Isabel O'Malley-Krohn, Pacific Collegiate School, Santa Cruz, CA: Trees for the People: Socioeconomic Distribution of Street Trees (2nd place High School division)
  • Caitlin Sullivan, Holy Cross School, Santa Cruz, CA: Effects of X-Ray Radiation on Plants (1st place Middle School division)
  • Ashlyn McDaniel, Baymonte Christian School, Scotts Valley, CA: Vinegar Stops Mold on Strawberries (2nd place Middle School division)