BFNA Title: Pylaisiadelpha
Author: W. B. Schofield
Date: November 22, 2009
Edit Level: R
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

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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, Central America. South America, Asia.


 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.