Saturday, October 7, 2017

Mosses of Central Florida 30. Atrichum angustatum

For other mosses in this series, see the Table of Contents]

Atrichum angustatum (Bridel) Bruch & Schimper (Polytrichaceae) is a relative of the common Polytrichum commune, but shorter in stature and with distinctly wavy leaves.  The upright stems are 1-2 cm tall, and like other members of the family, have vertical, fin-like sheets of tissue arising from the nidrib. Typically numbering about 10, these lamellae are also wavy.  Polytrichum has up to 20, and these are straight, compact and occupy most of the leaf surface. leaf cells are roundish and bulging to papillose  (with short, hard, translucent bumps).

The upward-facing rosettes of narrow, wavy leaves resemble a tiny bromeliad. The lamellae can be seen along the midrib,  running the length of the leaf. All photos by Robert A. Klips, Ohio Moss and Lichen Association. 
The wavy sheets of tissue, or lamellae, can be seen arising from the midrib.
Atrichum angustatum occurs throughout eastern North America, as far west as Nebraska and Texas, and as far north as Newfoundland. It can be found typically on exposed soil along roads and trails, as well as on soil exposed by fallen trees. It is uncommon in Florida, with just a few specimens from the northern part of the state down to Manatee County. It has been found in our area on creek banks and Indian mounds.


This reproductive specimen, with its narrowly cylindrical
sporangia, was photographed in Ohio.
This species may be limited in its abundance, in part, because male and female reproductive organs are borne on separate plants, which must occur in close proximity in order to form spores.  Sporangia, when found, are upright and narrowly cylindrical.






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