Pottiales

Article By:

Crum, Howard Herbarium, University of Michigan, Ann Arbor, Michigan.

Last reviewed:January 2021

DOI:https://doi.org/10.1036/1097-8542.540600

An order of the true mosses (subclass Bryidae), consisting of three families and about 91 genera. The order is characterized by short, papillose leaf cells and deeply divided, commonly twisted peristome teeth (see illustration). Members of the Pottiales typically grow erect, with stems simple or forked by subfloral innovation, and they often produce gemmae (asexual reproductive bodies) on leaves, stems, or rhizoids. The leaves have revolute margins, and are arranged in many rows. The single costa often ends in a hyaline hairpoint. The upper cells are short and thick-walled and often roughened with numerous C-shaped papillae. The alar cells are not differentiated, although the basal cells sometimes extend up the margins as a border. The cylindric capsules are generally exserted and usually erect. An operculum is usually differentiated, and the peristome, usually present, consists of 16 teeth which are often deeply divided into two filiform segments and papillose-roughened. The calyptra is usually cucullate. The chromosome numbers are generally 12, 13, or multiples thereof. See also: Bryidae; Bryophyta; Bryopsida

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