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BFNA Title: Macromitrium |
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5. Macromitrium Bridel, Musc. Rec.
suppl. 4 (Mant. Musc.): 132. 1819 *
[Name refers to long, large calyptra] Dale H. Vitt Plants in dense mats on rocks and
trees. Stems creeping with numerous, ascending to erect, simple or
forked branches. Branch leaves contorted, spirally
twisted, or crisped, rarely erect-appressed when dry, lanceolate, obtuse,
sometimes apiculate; margins entire to crenulate; costa percurrent to
excurrent; distal laminal cells rounded, bulging, papillose or mammillose;
basal laminal cells elongate, thick-walled, tuberculate or smooth. Sexual
condition autoicous. Seta 5--12 mm, dextrose. Capsule
ovate, becoming narrowly ovate to ovate-oblong when old and dry, plicate
below mouth; exothecial cells not differentiated; stomates superficial at
base of capsule; peristome single, of 16, rudimentary, pale, delicate,
sparsely-striate teeth. Stomates superficial. Calyptrae
mitrate, usually covering more than 1/2 the capsule, plicate, lacerate. Spores
isomorphic or anisomorphic. Species
ca. 460 (1 in the flora); North, Central, and South America, Asia, Africa,
Australia. Prostrate
creeping stems with numerous short, erect branches having terminal
sporophyte, a mitrate, plicate calyptra, and a propensity for a chestnut
brown color are generic characteristics. 1. Macromitrium richardii Schwägrichen, Spec.
Musc. Suppl. 2(2): 70. 173. 1826 Branches to 1 cm. Branch leaves
strongly crisped and inrolled when dry, lanceolate to ligulate-lanceolate,
0.7--1.8 mm, sharply acute, obtuse, or obtusely apiculate; distal laminal cells
7--11 µm wide, irregularly hexagonal to rounded-elliptic, bulging at mid
leaf, grading to papillose-bulging at tip; basal laminal cells rectangular to
elongate-linear. Perichaetial leaves similar to the cauline. Calyptra mitrate, naked, or with few hairs covering entire
capsule. Spores 22--32 µm, densely papillose. Capsules
mature spring. Branches and trunks of
trees; low elevations; Fla., La., Miss.; Mexico; West Indies; Central
America; South America. The only species of Macromitrium occurring in the United
States, this species is distinguished from other mosses with creeping stems
and erect branches by the non-rugose, inrolled leaves, and the uniformly
elongate basal leaf cells. The
papillose-bulging distal leaf cells and autoicous sexual condition
distinguish this species from other species of Macromitrium in the tropical portions of its range. |
