Bryophytes of Santa Barbara

Mesoptychia polymorpha Stotler, Crandall-Stotler & Bakalin

Mesoptychia polymorpha is a tiny, light green, leafy liverwort (3-6 mm long, and 0.6-1.5 mm wide) with two rows of irregularly shaped leaves on either side of the stem, and sometimes a third row of underleaves, which are just a few cells long. It is has been found on moist, shaded, calcareous, vertical substrates, particularly near waterfalls, at only a few locations in coastal California, and one site in Oregon.

Scroll down for photos with labeled parts and more detailed descriptions.

Mesoptychia polymorpha in situ — *Mesoptychia polymorpha* CC BY-NC Amanda Heinrich

Detailed Descriptions with Photos (click to enlarge)

Mesoptychia polymorpha has two rows of irregularly shaped leaves on either side of the stem. These leaves may be widely spaced as in the plant shown here, or more contiguous. Underleaves are apparently sometimes present but also deciduous, and very small, at only 2-6 cells long. A possible two cell underleaf may be present on the plant shown here.

Mesoptychia polymorpha has 2-8 oil bodies per cell. These can generally only be seen in freshly collected plants.

*Mesoptychia polymorpha* leaf cells with oil bodies. CC BY-NC Amanda Heinrich

Habitat and Distribution

Mesoptychia polymorpha is found on moist, shaded, calcareous and often vertical substrates, particularly near waterfalls. Shown here is the habitat at Nojoqui Falls in Santa Barbara. Mesoptychia polymorpha plants are primarily in the dark “cavelets” in this photo, scattered amongst other bryophytes.

Mesoptychia polymorpha habitat — *Mesoptychia polymorpha* on tufa at Nojoqui Falls. CC BY-NC Amanda Heinrich

Mesoptychia polymorpha is known from only a few locations in coastal California. Here in Santa Barbara County I have seen it only at Nojoqui Falls.

Name: The genus name, Mesoptychia, refers to the weak plications of the leaves (mesos = Greek for middle, ptychos = Greek for plica). The species epithet, polymorpha, refers to the irregular shape of the leaves (poly = Greek for many, morpha = Greek for shape).