The wild orchids of California. Cornell University Press, New York. The plants grew with Clarkia amoena susbp. The plants are erect either simple or with erect branches, slightly puberulent. The leaves are linear to lanceolate with short petioles or sessile.
Flower buds are erect and flowers are sessile with reflexed sepals and purplish or crimson petals.
From the phytogeographical point of view this species belong to an interesting group of species that occur from coastal California to coastal northern Oregon and are rare or entirely absent in Washington. B.C. Myriophyllum pinnatum belongs to the section Tessaronia. M. pinnatum differs from all other species of Tessaronia by having ridges of the fruit covered with sessile glands. Sterile specimens are difficult to identify since they can be confused with M. hippuroides which is quite frequent in the lower Fraser River Valley. In nearby Pitt Lake, we collected strange specimens with wiry stems in 1979, but we were unable to identify them since we could not find fertile specimens.