Mosses of Central Florida 28. Climacium americanum

The branching, tree-like form of Climacium americanum, and the
cylindrical, upright spore capsules, distinguish this species from
others. Photo courtesy Robert A. Klips, 
Ohio Moss and Lichen Association.

Climacium americanum Bridel (Climaciaceae) is a distinctive moss with a "tree-like" shape, and often of a yellow-green color.  It has upright stems that branch out into a number of spreading, leafy branches. It occurs in our area in wet habitats, most often on decaying logs in cypress swamps, but elsewhere in damp soil along rivers or marshy depressions.

In Florida, this species is distributed from the northern counties southward to Manatee County, with some records from Broward and Monroe counties.  It also occurs widely northward in the eastern U.S. and Canada, the Rocky Mountains,  Pacific Northwest, and Alaska.

The leaf has a distinct midrib, which tapers out just short of the leaf tip, jagged teeth in the upper part, a broad, spreading base without inflated cells, and cells that are "worm-like" (elongate,  tapered, and slightly wavy). Between the leaves are many branching, thread-like appendages called paraphyllia.

The broad leaf base and tapered tip of the leaf of Climacium 
americanum give it a triangular shape. Photo courtesy Robert A. 
Klips, Ohio Moss and Lichen Association/.

The spore capsules are erect, symmetrical, and narrowly cylindrical.

Although it was collected a number of times in our local Hillsborough River Basin in the 1970's, I have yet to find living specimens myself.  So I am grateful to Bob Klips of the Ohio Moss and Lichen Association for the use of his photos.

The worm-like cells of Climacium can be seen in this photo from
Wikimedia Commons of C. dendroides (not in our area).