The long-lost Artist's Popcorn Flower has been found!

Today’s Glimpse from the Field is the latest edition of David and Doug's San Bruno Mountain Rare Plant Alert email. Their just-released discovery was made in February 2017 but it took a couple of months to confirm the plant identity. David Nelson and Doug Allshouse are on the Mountain every Saturday in their search for interesting, rare and endemic plants - this ongoing research is the basis for their upcoming book. Together they are writing "The Natural History of San Bruno Mountain", a long-needed and detailed natural history of the Mountain. The book will be published by the California Native Plant Society.

David Nelson, aside from being a surgeon, is a devoted Mountain Watcher and amateur botanist. Doug Allshouse is an expert on San Bruno Mountain flora & fauna who has studied the Mountain for 38 years. They send out regular SBM Rare Plant Alert emails to interested persons. David can be contacted at nelsondl@pacbell.net and Doug at dougsr228@comcast.net. Contact David if you would like to be on the SBM Rare Plant Alert List.


This is the biggest announcement since 5/4/16, when we announced the rediscovery of Silene verecunda, the finding of the second group of Arctostaphylos uva-ursi forma leobreweri, and the discovery of the long-lost Tanacetum bipinnatum.  Doug and I have been waiting until we could get professional confirmation of our ID, but can now let you know that the long-lost Plagiobothrys chorisianus, Artist's Popcorn Flower, has been found!

This plant was cited as one of the "species of concern" that the 1982 HCP was designed to protect (cited by a previous name, Allocarya chorisiana). It had been collected by Elizabeth McClintock in 1962 and again by Walter Knight (co-author with McClintock of the 1968 and 1990 editions of Flora of the San Bruno Mountains) in 1965. According to Paul Reeburg, co-author of the 1990 Flora, it probably had not been seen by the authors since. It was last collected on San Bruno Mountain in 1985 by Robert Norris. It has not been seen for 33 years and has been widely presumed lost, using the criteria of "not seen in 20 years", which is a standard used by the CNPS.

On February 25, while exploring April Brook, Doug sighted a Primula hendersonii (shooting star). I was photographing it when Doug and Mark Sustarich saw something different - and suggested that I stop standing on it! You might be able to excuse my standing on this rarity when you realize how small it is.

Doug quickly recognized the one plant with flowers (see above) as a member of the Boraginaceae. They were so immature (only about 2 cm tall), it was hard to tell which Boraginaceae, since so many have identical flowers.

Back home, our team scoured CalFlora, eJepson, and the FNA, and narrowed it down to two possibilities.  I sent photos off to Ron Kelley, the Boraginaceae section editor for Jepson. He recognized the species based on the photo below.

Note that the pedicels elongate as the scorpioid cyme unfolds.The length of the pedicel identifies this species, as well as the very long hairs on the edge of the leaves but not on the leaf surfaces.

San Bruno Mountain has about 100 plants, only in one area, 0.5 m x 2 m, so although "rediscovered", they are still quite vulnerable. We are developing a management plan for submission to Ramona Arechiga, Natural Resources Manager for San Mateo County.

Its original discovery was by Chamisso, the botanist aboard the Russian ship Rurik, commanded by Kotzebue, on a voyage of scientific and political exploration. They were looking for the North East Passage as well as trying to establish Russian ownership of the Pacific coast in opposition to the claims of Spain.  The Rurik moored in SF Bay in 1816 (the Spanish quickly manned their guns before the peaceful nature of the visit became clear). Chamisso likely only explored near the town, as they only had one month, in October, to collect. San Francisco is, therefore, the type location of the plant, which is found only along the central California coast. Chamisso described it in Latin in 1829, naming it for the artist of the expedition, Ludwig Choris, hence the specific epithet chorisianus and the common name, Artist's Popcorn Flower.

The purpose of the San Bruno Mountain Alert is to foster information exchange among those who love the Mountain. Please let us know of your discoveries.

David & Doug

References:

California Consortium of Herbaria search for Plagiobothrys chorisianus

Voyage of the Rurik