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BFNA Title: Pylaisiadelpha |
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XX. PYLAISIADELPHA Cardot, Rev. Bryol. 39: 57. 1912 * [Genus Pylaisia and Greek adelphos,
brother, resembling Pylaisia] W. B. Schofield† Plants slender to robust, forming glossy green
to yellow-green mats, to 3--4 cm, branching regular to irregular, the
branches sometimes arching upward, or prostrate. Stems
creeping, red-brown, densely foliate; pseudoparaphyllia filamentous to
narrowly foliose. Leaves homomallous, falcate-secund to erect-spreading, sometimes
complanate, lanceolate to ovate, narrowly acuminate, entire except near
acumen; costa double, short, or absent; laminal cells smooth, somewhat
flexuose medially, alar cells slightly to somewhat enlarged, usually
pigmented. Specialized asexual reproduction by axillary filamentous
propagula. Sexual condition dioicous. Seta
smooth, about 0.5 cm, reddish. Capsule
usually inclined, sometimes erect, usually symmetric, ovoid to cylindric,
exothecial cells not collenchymatous; peristome double. Species 4 or 5 (1 in the flora); temperate areas of North
America, The distribution of
Pylaisiadelpha is difficult to
assess. W. R. Buck (1998) states that
“the genus is particularly diverse in the Asian tropics” apparently basing
this on his wholesale transfer of many species of Brotherella (W. R. Buck 1984).
A monograph is greatly needed. SELECTED REFERENCES Buck, W. R. 1984. Pylaisiadelpha replaces Brotherella (Sematophyllaceae). Yushania 1(2): 11--13. Buck, W. R. 1998.
New combinations and new synonymy in Brazilian Sematophyllaceae. Nova Hedw.
66: 241--246. 1.
Pylaisiadelpha tenuirostris (Bruch & Schimper in A. Gray) Buck, Yushania 1(2):13. 1984 Leskea tenuirostris Bruch & Schimper ex Sullivant in A.
Gray, Manual, 228. 1848; Brotherella tenuirostris (Bruch &
Schimper ex Sullivant) M. Fleischer Plants small. Stems 1--4 cm, slender, forming mats of irregularly to pinnately
branched reclining shoots, yellowish green, weakly glossy, weakly complanate;
stem reddish with narrow foliose pseudoparaphyllia. Leaves
of stem and branches similar, crowded, erect-ascending to falcate-secund,
lanceolate to oblong-lanceolate, stem leaves 0.7--1 mm, branch leaves
slightly smaller; alar cells colored, lowermost row enlarged; supra-alar
cells also distinct. Specialized asexual reproduction by
filiform propagula in axils of leaves.
Sexual condition dioicous. Capsule
erect and symmetrical, ca 1 mm; operculum long-rostrate. Rock and epiphytic on tree trunks and bases, also logs,
mainly in broadleaf woodland, where uncommon; low to moderate
elevations; Nfld., N.S., Ont., Ala.,
Ark., Conn., Ga., Ill., Ind., Md., Me., Mich., N.Y., N.C. Ohio, Okla., S.C.,
Tenn., Va., Vt., W.Va., Wis.; Mexico; Central America; Asia. Pylaisiadelpha
tenuirostris is
superficially similar to some specimens of Hypnum pallescens, a commonly sporophyte-bearing species with
conic opercula and leaves lacking enlarged alar cells. Sporophytes are rare. The rostrate opercula
and conspicuous coloured enlarged alar cells are distinctive. |
