This plant is rare/threatened/endangered, and endemic to the Bay Area only. We saw it from Road F, below the new construction on neighboring land. Teal asked me to share this with Nona, and John R. Nona reports:
"Some of you had recently spotted what appeared to be
CHAPARRAL MALLOW in bloom south of the boundary fence. Nona then visited the occurrence and photographed some of the diagnostic characters. Keir Morse, who has been working with our sheets at Rancho Santa Ana (aka California Botanic Garden), subsequently identified these plants as
Malacothamnus arcuatus <
https://www.inaturalist.org/observations/167012394 >
« Malacothamnus arcuatus (M. fasciculatus) CHAPARRAL MALLOW Flickr Calflora eFlora SPEC Springer 1935 Sphaeralcea arcuata “infrequent”. Keir Morse (2022) Systematics and Conservation of the Genus Malacothamnus Re:
Malacothamnus fasciculatus: "Plants from Jasper Ridge are
M. arcuatus. This taxon was not recognized (even as a synonym) by Tracy Slotta, but is recognized by CNPS and, based on my current research, will probably be recognized in future . . . " (Keir Morse 2019-06-20)
· Malacothamnus arcuatus [Rank 1B.2] (rare, threatened, or endangered in CA and elsewhere). [Malacothamnus fasciculatus (Nutt. ex Torr. & A. Gray) Greene.] Calflora Check out Nona's nice macros on iNaturalist!