Coming Soon! Checklist of the Plants of San Francisco, 3rd Edition


The global pandemic has put a serious crimp in our travel plans. In January, we were all set to begin exploring the South Pacific, starting with New Caledonia (to see the serpentine soils and native stands of Araucaria), and hopping our way towards SE Asia. But after two months in New Zealand and with typhoon season about to start we decided to take a break in Hawaii before picking up the trail again. Then the world changed. We found a comfortable spot near the beach in Kailua, Oahu, close to relatives, and set up house. I won’t bemoan our predicament…there are worse places to get stuck. And we’re counting our blessings that we weren’t in the Solomon Islands when the pandemic hit. But after sitting still for ten months now, we’re ready to move on.

One can only take so much of paradise and we needed more to do than sit under coconut palms on the beach. After some encouragement from my CNPS colleague Peter Brastow, I decided that this was an ideal time to update our chapter’s checklist of the plants of San Francisco. In the six years since releasing the second edition, many surveys of our natural areas have been completed and a lot of new data have been collected. There have been a lot of boots on the ground as part of weed eradication and habitat restoration efforts. Old species have been rediscovered or reintroduced, others have faded from view, and the invasives continue their spread. There have been some notable taxonomic changes and rarity ratings have changed. So, it made sense to issue an update. I figured it would take six months and had hoped to have it ready for release by September, when the world would open up and we could resume our travels. No such luck on either count.

In 2013, I wrote a pair of articles about our Annotated Checklist of the Vascular Plants of San Francisco’s Natural Areas[1]. Then as now, it is my wish that the checklist serve as a sort of clearinghouse of data regarding San Francisco’s plant diversity, as an aid to volunteer groups working to protect our natural heritage by identifying invasive species that are overwhelming natural habitats, and to help guide and perhaps inspire fans of our flora while exploring our hills, dales, and oh-so-scenic coastline. This led to three spin-off projects: a Checklist of the Extirpated Plants of SF[2], a list of the rare plants of SF, and a list of the Locally Significant Plants of SF[3]. Finally, I parsed out the occurrence data to produce individual checklists for 58 of the city’s natural areas. All of these lists are available as free, downloadable pdfs[4].

So what’s new about the third edition, you ask? Lots. First and foremost are the names. This might elicit some moans of dismay but the taxonomists have been hard at work redefining familial relationships, reassigning genera and lumping and splitting taxa. Some notable shifts since the second edition include: Orobanche is now Aphyllon; Mimulus gutattus and M. cardinalis are now in the genus Erythranthe while M. aurantiacus has been moved back to Diplacus; Dichelostemma capitatum is now Dipterostemon capitatus; Dodecatheon has been moved into the genus Primula; Thysanocarpus curvipes has been divided into five subspecies; and the fern genus Athyrium has been moved from the Woodsiaceae to the Athyriaceae.

In the 2014 edition of the checklist, taxa were sorted by family, an arrangement that many users found, well, confounding. For the third edition, taxa will be sorted alphabetically by genus, with a three-letter code to indicate families. For those users who think in terms of families, I have created a separate table listing all plant families covered in the checklist along with each genus to aid in cross referencing.

In terms of content, I have added a column to indicate taxa that are endemic to San Francisco, the Bay Area, or California. The “notes” field now includes a list of all locations from which each native taxon has been collected or reported historically (prior to 1980) and the earliest year in which each was recorded. The checklist now includes all taxa that are presumed indigenous to SF but that have not been seen since 1980 and are therefore presumed extirpated; the date of the last record has been added and all extirpated taxa are highlighted making them easy to spot when scanning the list. The “notes” field includes the name of all locations at which each taxon is believed extant. I have expanded the list of natural areas to include some parks but have avoided including highly contrived sites that have little value in terms of the native species that might be found there. All rarity rankings have been updated, as have invasive ratings per the California Invasive Plant Council, US Dept. of Agriculture, California Dept. of Food and Agriculture, and the San Francisco Weed Mgt. Area.

In the course of updating the list I made a careful review of the online records in the Consortium of California Herbaria (CCH), reviewing every collection made in San Francisco. I’ve updated synonymy per the Jepson Online Interchange for California Floristics. Synonyms are included in the “notes” field and all names cited in the 1958 flora are underlined to facilitate cross-referencing. Regarding reported occurrences not supported by herbarium specimens, I have continued to include reports from reputable (and a few quasi-reputable) sources. As before, these include lists compiled by long-time CNPS members as well as lists generated by the Presidio Trust, Golden Gate National Recreation Area staff, the dedicated staff of the Natural Areas Program, published and unpublished lists, and planning documents. I have reviewed all San Francisco reports contained in the Calflora database and, with a very high degree of caution bordering on skepticism, iNaturalist records.

Meanwhile, Dr. Tom Daniel, Curator of Botany, Emeritus, at the California Academy of Sciences, continues his daunting task of writing a new flora of San Francisco. Tom reports that his work will present an update of the native and naturalized occurrences of plants in San Francisco County via a book/field guide that will include an introduction to the vegetation and flora of the county; identification keys to all genera and species; accounts of each species that will include scientific and common names; brief description of morphological features, habitats, whether native or naturalized; previous (pre-1957) and more recent collection and observation locales; notes on  nomenclature, natural history, and ethnobotany; and many color photos and line drawings. While no date has been set for its completion, he hopes to release it by the end of 2022.

Until then, I hope our modest effort will continue to be of use. Check our chapter website for an announcement of its availability.

By The Numbers

The checklist has grown substantially in terms of length and the number of taxa included.

2nd ed.
3rd ed.
Total Families*: 125 131
Total Genera*: 534 651
Total Taxa*: 1231 1640
Total SF Indigenous Taxa*: 672 778
Total Non-Native Taxa*: 417 862
Total Extant Taxa: 1027 1172
Total Extant Nonnative Taxa: 417 572 48.8%
Total Extant SF Indigenous Taxa: 468 508 43.3%
SF Indigenous Status Uncertain: 9 28
Total Extant Taxa Native to CA: 535 591
Total Extant Invasive Taxa: 103 160 13.7%
Total Extirpated SF Indigenous Taxa: 204 271 34.8%
Total Reintroduced Taxa: 17 24
Total fed/state/CNPS List 1-3 Taxa: 24 19
*extant and extirpated taxa

[1] Part 1:

Part 2: