|The tiny rosettes of Ephemerum crassinervium
appear scattered on a mass of green,
thread like stems (protonemata). Photo by Robert
A. Klips, Ohio Moss and Lichen Association.
The tiny rosettes are only a few mm high, though the spreading leaves may be as much as 2.5 mm long. Leaves are toothed in the upper 2/3 and papillose (with small, translucent bumps) at the tip. The midribs are weak, sometimes not evident at the base. Leaf cells are irregularly long-rectangular and lined up in vertical rows.
|The spherical spore capsules are also tiny and
often overlooked. Photo by Robert A Klips,
Ohio Moss and Lichen Association.
Ephemerum crassinervium is found widely in eastern North America, west to Texas and Nebraska, north to Saskatchewan, Ontario and Quebec (but not known in Maine), with some reports from Oregon. In Florida, it has been sparsely collected from the panhandle to Collier County.
Two additional species have been reported from Florida. E. cohaerens has been even more sparsely collected throughout north Florida, but not yet in central Floirda. It differs from E. crassinervium in the smoother cells of the leaf tip, and the leaf cells lined up in diagonal rows.
E. spinulosum has a similar distribution as C. crassinervium, with some in Hillsborough and Manatee counties; cells of the leaf tip are spiny as opposed to smooth or papillose.