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BFNA Title: Trachybryum |
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XX. Trachybryum (Brotherus) W. B. Schofield, J. Hattori Bot. Lab. 31: 222. 1968
* [literally “rough moss”] Camptothecium sect. Trachybryum Brotherus in Engler
& Prantl, Nat. Pfl.
1(3): 1140. 1980. W. B. Schofield Plants robust, forming loose mats, usually
yellow-green but in deep shade often dark green, glossy.
Stems prostrate, with central
strand, densely terete-foliate, regularly to
irregularly (and remotely in grassy habitats) pinnate branched in one plane,
flattened when wet, coiling upward when dry; branches pointed to strongly
attenuate; axillary hairs 4--5-celled; juvenile
branch leaves acuminate. Stem leaves imbricate
when dry, erect, ovate-lanceolate to lanceolate, broadest in proximal 1/10 leaf length, gradualy tapered along most of its length and rather
shortly acuminate, very slightly tapered to base, very shortly decurrent, slightly concave, strongly plicate, margins
plane or recurved at places, entire or with sparse,
indistinct blunt teeth; costa strong, extending
nearly to leaf tip, often with 1--2 teeth at end; basal cells near costa in 2--3 rows shorter and wider, with strongly
incrassate and porose cell walls; cells just
proximal to decurrency somewhat broader,
rectangular, thick-walled, forming a small, more or less distinct group not
reaching leaf margin or sometimes indistinct; mid leaf cells very narrow,
linear, smooth. Branch leaves smaller
and narrower than stem leaves, less attenuate, serrulate
or at places almost subentire; alar
cells few, often inconspicuous, median leaf cells narrow, 10--20:1. Sexual condition dioicous
or phyllodioicous; sporophytes
uncommon; perichaetial leaves reflexed,
gradually acuminate from a sheathing base, entire or occasionally serrulate, costa weak and
short, reaching to about half of basal part of leaf. Seta red-brown, rough. Capsule
red-brown, horizontal, ovoid-oblong, swollen at base, tapering to mouth,
curved; annulus separating by fragments; operculum long-conic; peristome perfect. Calyptra naked. Spores 19--20 \um,
nearly smooth. Species 1:
western Trachybryum
is distinct in its
large size, lack of rhizoids due to dense stem foliage, stem leaves that are
considerably larger than branch leaves, weakly differentiated alar cells, and a distinctive ecology, occurring usually in
conifer forests on litter, not on rocks and trunks as do most Homalothecium species. SELECTED
REFERENCE 1. Trachybryum
megaptilum (Sullivant) Schofield, J.
Hattori Bot. Lab. 31: 222. 1968 Camptothecium
megaptilum Sullivant, Icon. Musc.
Suppl., 102. 1874; Homalothecium megaptilum (Sullivant) H. Robinson Stems 1--12 cm, branches 10--15 mm. Stem leaves 3.5--5 x 1.3--1.8 mm;
basal cells near costa 30--60 x 9--12 \um wide,
just proximal to decurrency 25--40 x 9--12(--14) \um;
mid-leaf cells 60--130 x 4--6 \um. Branch
leaves 1.8--2.5 x 0.8--1.2 mm; mid-leaf cells 50--90 x 4--6 \um. Seta 2--2.5 cm. Capsule 2--2.5 mm. Litter in
coniferous forest, among grasses in open sites, rarely logs and rocks;
(60--)300-1300 m; B.C.; Calif., Ida., w Mont., Ore., Wash. |