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BFNA Title: Taxithelium |
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Taxithelium – Sematophyllaceae W. B. Schofield† XX.
TAXITHELIUM Spruce ex Mitten, J. Linn. Soc. Bot. 12: 21, 496 1869 * [Greek taksi,
order, and thele, nipple,
alluding to single row of papillae over cell lumens] Plants slender to medium-sized, in thin to
dense creeping mats, dull yellow-green to brownish. Stems 1--3 cm, creeping,
irregularly to regularly pinnate. Branches
usually short, 0.2--2 cm, usually complanate foliate, sometimes with
spreading lateral leaves and dorsal and ventral leaves smaller and appressed,
contracted at clasping base. Stem leaves narrowly to broadly ovate
to ovate-lanceolate, apex blunt, acute or acuminate, margins entire or weakly
to sharply toothed, teeth often in pairs; costa short and double or absent;
laminal cells rhomboid to linear, strongly to faintly 1-seriate papillose
over lumen, occasionally smooth; alar region usually differentiated with
somewhat elongate, sometimes inflated proximal cells, hyaline or colored,
supra alar cells few to many, subquadrate, in 1--2 rows, often with 1 row
extending up margin. Branch leaves similar
to stem leaves. Specialized asexual
reproduction rare, by filamentous
gemmae. Sexual condition autoicous or dioicous; perichaetia and perigonia
on stems or bases of branches. Seta elongate,
smooth. Capsule ovoid, inclined to horizontal; exothecial cells not or
weakly collenchymatous; peristome double, exostome and endostome teeth of
equal length, alternate; exostome of 16 subulate striolate teeth, endostome
with medium to high basal membrane, cilia 1--3, appendiculate; operculum
conic with short or long rostrum. Calyptra smooth, cucullate. Spores
spherical, 12--22 \um, smooth to finely papillose. Species about
40 (1 in the flora): tropical and subtropical. North America, South America,
Central America, Asia, Africa, Taxithelium occurs mainly in forests, generally as
corticolous on tree trunks and branches, but also on logs, occasionally on
rock and soil. SELECTED
REFERENCES: Buck W. R. 1985. A review of Taxithelium (Sematophyllaceae) in 1. Taxithelium planum (Bridel) Mitten, J. Linn. Soc. Bot. 12:
496. 1869 Hypnum planum Bridel, Muscol. Recent., Suppl. 2: 97.
1812 Plants slender. Stems usually less
than 10 cm, yellow-green, somewhat glossy, subpinnately branched. Leaves
short-acuminate; alar cells differentiated but without row of inflated,
elongate cells; leaf cells smooth or 1-seriately multipapillose. Sexual
condition autoicous. Bark of trees and
on exposed roots and rotten logs; Fla.; Mexico; West Indies; Central America;
South America; Asia; Africa; Australia. |
