Wednesday, February 7, 2018

Mosses of Central florida 46. The genus Leskea

Leskea gracilescens growing on the side of a tree.  Photo by
Robert A Klips
Three of the four species of  Leskea found in North America have been reported from Florida: Leskea australis Sharp,  L. gracilescens Hedwig, and L. obscura Hedwig.   These are creeping, irregularly branched, mat-forming mosses, often with a reddish coloration, found on the bases or lower trunks of hardwoods and cypress trees, or on decaying logs. 
A leaf of Leskea gracilescens, showing the small roundish
cells with papillae (translucent light spots).  Photo by Kalman
Strauss, posted in the Consortium of North American
Bryophyte Herbaria database.
Leaves are ovate and pointed, with midribs that usually end before the tip.  Leaf cells are small, roundish, and papillose, and the spore capsules are erect and more-or-less symmetrical.

Only Leskea australis is known from central Florida.  It has been found throughout the state, but has not been reported from the extreme south, the western panhandle or the Atlantic coastal counties. Elsewhere, it is found throughout the southeastern U.S.
A leafy shoot of Leskea gracilescens with an inset of the
papillose leaf cells.  Photo by Robert A.Klips

The erect, symmetrical spore capsules of Leskea gracilescens.
Photo by Kalman Strauss.

L. gracilescens and L. obscura are both widely distributed in eastern North America, live in the same habitats as L. australis, and differ in minor ways. L. grascilescens has been reported from several counties in North Florida, elsewhere throughout eastern North America, and L. obscura only from Leon County.

Our Leskea species are similar to Haplocladium microphyllum, also in the Leskeaceae, but in Haplocladium the spore capsules are bent distincly to the side, and the leaf tips more drawn out into a narrow point.  H. microphyllum is also more likely found in soil, rocks or damp wood than on tree trunks. 

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