Vernal pool vegetation of California: communities of long-inundated deep habitats

Vernal pools contain ephemeral wetland vegetation in the class Downingio bicornutae-Lasthenietea fremontii. In this article, those communities with the longest period of inundation were classified into a new order Lasthenietalia glaberrimae, the alliance Lasthenion glaberrimae, four associations, seven variants, and one unranked community. The analysis was based on vernal pools in northern California. The Downingio bicornutae-Lasthenietum glaberrimae characterizes duripan vernal pools on foothill terraces. It is the most widely distributed association of the four, and it contains seven variants. The Pogogyno douglasii-Lasthenietum glaberrimae is more restricted to higher elevation basaltic table mountains. The Trifolio variegati-Lasthenietum glaberrimae is characteristic of relatively shallow pool bottoms on foothill terraces. Finally, the Pleuropogono californici-Lasthenictum glaberrimae occurs in slightly saline claypan pools located in the valley floor. The Eleocbaris macrostachya [Lasthenion glaberrimae] community represents floristically depauperate stands. The syntaxa tend to be locally restricted and their diagnostic species are typically related to the period of inundation.