Monday, March 16, 2015

Mosses of Central Florida 11. Haplocladium microphyllum

Haplocladium microphyllum is frequently found growing in wet, sandy soil
in lawns.
[For other mosses in this series, see the Table of Contents]

Haplocladium microphyllum (Hedw.) Broth. (Leskeaceae)  is a creeping, mat-forming moss that is widespread globally, across much of Eurasia, South America, and in North America from Florida to Texas and up to southern Canada.

This species superficially resembles Isopterygium tenerum.  They are both prostrate, mat-forming mosses growing at the bases of trees, but Haplocladium is more likely to be found on soil, frequently in lawns, and often found on or near concrete or other alkaline materials.  Their capsules are essentially indistinguishable from those of Isopterygium, without examination of minute technical details.
Haplocladium colonies can sometimes be seen creeping
up on bricks or concrete surfaces.

The capsules of Haplocladium are curved to the
side as in Isopterygium.
The leaves of Haplocladium are short but slender-tipped, and
have a prominent midrib.
It is in their leaves that Haplocladium can be most easily distinguished from similar species.  The leaves of Haplocladium are shorter, but with more prolonged tips, and more pressed against the stem than those of Isopterygium, especially when dry.  The leaves also have a strong midrib, lacking in Isopterygium, and the cells are roundish to square, instead of long and worm-like.  The cells are also papillate, i.e. with short, hard, pimple-like projections.
The leaf cells are squarish and have a single hard
papillum (seen as a bright spot on the out-of-focus
cells to the sides). Part of the midrib is on the left.

Species in the genus Entodon have a similar creeping habit, but their capsules are upright and cylindric.