Today’s Glimpse from the Field is the latest edition of David and Doug's San Bruno Mountain Rare Plant Alert email, from December 2016 - adding yet another report on our Mountain's manzanitas. 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 email@example.com and Doug at firstname.lastname@example.org. Contact David if you would like to be on the SBM Rare Plant Alert List.
Arctostaphylos uva-ursi forma suborbiculata (Miniature Manzanita) is endemic to San Bruno Mountain and has to date only been found on the southeast corner of Kamchatka Point. Recently Doug and I found a second, much larger patch of suborbiculata, along the ridge separating Cable Ravine from Dairy Ravine.
We were looking for Gaultheria shallon, salal - in the same plant family as manzanita - Ericaceae. The plant is listed in Elizabeth McClintock 1990, but we have not seen it to date. (If you have seen it, please tell us!) We did not find the salal, but we found a great substitute, the suborbiculata.
If you are interested in the plant characteristics, they are: form prostrate/mounding, height 10 cm, twig short hairy, dense, nonglandular; leaf short, dense hairy margins; nascent inflorescence hairy glandular; leaf orientation spiral & erect; petiole to 5 mm; leaf size 14-15 mm by 8-9 mm; margin entire, hairy; leaf base acute, leaf tip usually rounded, but many acute; bifacial, with dark top and lighter bottom; stoma top occasional and hairy, bottom many; inflorescence typical Arctostaphylos dependant racemes, white to light pink, not as pink as leobreweri. These characteristics match our analysis of the Kamchatka Point suborbiculata, so we are confident in the ID.
This is an important find because suborbiculata is endemic to San Bruno Mountain and this find both increases the known plant area by about 30X, and also identifies only the second area where it grows. The two stands are close together, so there is not much protection from fire, etc.
David & Doug
Gaultheria shallon photo: Gerald & Cori Buff, © California Academy of Sciences, 2007