Thuidium

• Authority

  Buck, William R. 2003. Guide to the plants of central french Guiana. Part 3. Mosses. Mem. New York Bot. Gard. 76: 1-167.

• Family

  Thuidiaceae

• Scientific Name

  Thuidium

• Description

  Genus Description - Plants small to robust, in typically stiff, dark green to golden, loose mats; stems creeping or ascending, mostly regularly 1-3-pinnate, in cross-section with a sclerodermis; paraphyllia present. Stem and branch leaves typically strongly differentiated, stem leaves usually broadly ovate, often abruptly acuminate; branch leaves smaller than stem leaves, lanceolate to ovate, usually gradually acuminate to obtuse; margins serrulate to crenulate ± throughout, usually plane, elimbate; costa single, weaker than in stem leaves; cells ± quadrate, uni- or pluripapillose on both surfaces or just at back, the apical cell typically truncate and pluripapillose; alar cells not or poorly differentiated. Asexual propagula none. Autoicous or dioicous. Setae elongate, smooth to roughened, either throughout or rarely just above, reddish; capsules mostly inclined to horizontal, rarely erect, mostly asymmetric and arcuate, cylindric; peristome double, exostome teeth on the front surface cross-striolate below, sometimes with overlying papillae, papillose above; endostome mostly with a high basal membrane, segments keeled, not to narrowly per¬forate, cilia in groups of 1-3, nodulose. Calyptrae cucullate, rarely mitrate, mostly naked, smooth or roughened. The Thuidiaceae are characterized by pinnately branched plants with strongly differentiated branch and stem leaves. The stems are usually amply clothed with paraphyllia, but in smaller plants paraphyllia are often sparse. The leaf cells, of both stem and branch leaves, are short and papillose. The Thuidiaceae were distilled to a more natural family by Buck and Crum (1990). Characters that were emphasized in defining the family and in delimiting genera were sexuality, placement of leaf cell papillae, papillosity of the cells of the paraphyllia, morphology of axillary hairs, and seta ornamentation.