Monday, August 21, 2017

Mosses of Central Florida 26. Dicranum condensatum

Dicranum condensatum Hedwig (Dicranaceae) grows in sandy soil throughout Florida, sometimes forming deep cushions made up of long, mostly dead stems and leaves, with green tips. The leaves along the stem are of the same size and shape and are produced indefinitely, in contrast with the related species Campylopus surinamensis.  It does produce spores, but apparently only rarely in our area.
A well-established clump of Dicranum condensatum nearly 6 cm deep.
Only the leaves in the top centimeter or so were alive when this specimen
was 
collected ( Lassiter 2077, USF)
Leaf cells of  D. condensatum are squarish-rectangular in the
upper part, and the margins of the leaf are toothed. 

Like all members of the family, the midrib (costa) of the leaf is massive, but not as broad as in Campylopus, occupying only 1/10 to 1/5 the width of the  leaf in the lower part. Leaves are mostly 3.5-4.5 mm long, and more or less curled or twisted at their tips when dry.  Cells are angular squarish near the tip, becoming more elongate toward the base, and distinctly larger and empty at the base (alar cells).



Leaves are twisted-curled when dry.
Two other species of Dicranum are found in Florida, but not as common or widespread.  D. scoparium is found in humus, rotting stumps, tree bases, and has short-sinuous leaf cells. D. flagellare, found only in north Florida, has specialized whip-like branches with short, scale-like leaves pressed to the stem that arise from the axils of ordinary leaves. The related Dicranella has much shorter leaves.  Ditrichum pallidum (Ditrichaceae) is sometimes confused with Dicranum. It grows in similar habitats, but typically has much longer leaves on shorter stems, resembling tiny clumps of grass.

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