Lessingia micradenia var, micradenia (Tamalpais Lessingia)
by Doreen Smith
The Marin County endemic species, Lessingia micradenia var, micradenia (Tamalpais lessingia) can be discovered in flower any time between late May and September but only in serpentinite areas.
It is an unprepossessing short, annual, rare plant (CNPS Rare Plant Rank 1B.2). When mature it’s very branched, wispy and slender with tiny few-flowered mauve composite heads.
The southernmost occurrence on record is from the area of Phoenix Lake on the N. side of Mt. Tamalpais and the northernmost site where I’ve seen it is at Forest Knolls on the Marin Parks’ French Ranch Open Space Preserve. As far as I know it is not at Big Rock Ridge, though there is suitable habitat. Most of George Lucas’s property there is private and not open to the public for exploration, with the exception of the Bay Area Ridge Trail easement.
Photos by Doreen Smith (habit) and Vernon Smith (close-ups)

Lessingia micradenia var. micradenia – (Mt. Tamalpais Lessingia)

Lessingia micradenia var. micradenia – (Mt. Tamalpais Lessingia)

Lessingia micradenia var. micradenia – (Mount Tamalpais Lessingia)