Two Ammania species (Lythraceae)

by Doreen Smith

There are few California native plants to choose from that flower during the month of September. Drying lake, lagoon, and reservoir shores can be places to discover some of them. Plants of aquatic and wet habitats are often widely distributed and included as natives in each country where they are present. Perhaps they have been spread by migrating waterfowl from their original prehistoric sources.
Two small unusual species from moist, drying, freshwater shores are in the Lythraceae: Ammannia robusta and Ammannia coccinea. The Jepson Manual #2 of 2012 treatment differs from that in Howell’s Marin Flora of 2007; I’m using the former. Ammannia robusta is the larger of the two species when in flower and has been found on the shores of the reservoirs on Mt. Tamalpais; the petals are lavender-pink. Ammannia coccinea is tiny, has red-purple petals, and is found around Nicasio reservoir.

Ammannia robusta – (grand redstem) Photo by Doreen Smith

Ammannia coccinea – (valley redstem) Photo by Vernon Smith