BFNA Title: Homalotheciella
XX. HOMALOTHECIELLA (Cardot) Brotherus in H. G. A. Engler & K. A. E. Prantl, Nat. Pfl. 1(3): 1133. 1908 * [diminutive of Homalothecium]
William D. Reese
Homalothecium sect. Homalotheciella Cardot, Bull. Herb. Boissier 7: 374. 1899
Plants small, creeping, yellowish green. Stems slender, pinnate; branches short, erect, often curved. Leaves on stems and branches similar, ascending, ovate-acuminate, nonplicate; margins serrate; apex slenderly acuminate; costa slender, sometimes indistinct, reaching midleaf or longer; medial cells elongate, smooth; alar cells quadrate in vertical rows. Sexual conditon autoicous; perigonia gemmiform, axillary on stem; perichaetia gemmiform, axillary on stem. Seta straight, elongate, papillose. Capsule erect, exserted, ovoid or slightly asymmetric, exothecial cells oblong-rectangular; stomates scanty, proximal on capsule; operculum obliquely rostrate; peristome double, exostome pale yellow-orange, teeth incurved-connivent when dry, spreading when wet, finely cross-striolate on outer surface, transversely ridged on inner surface, fimbriate-bordered, papillose at tips; endostome low, inconspicuous, imperfect, adherent to teeth. Calyptra bearing a few slender 1-seriate hairs.
Species 2(--3)(1 in the flora): eastern North America, Central America (Guatemala); South America (Guyana), Asia (China).
SELECTED REFERENCE Robinson, H. 1962. Generic revisions of North American Brachytheciaceae. Bryologist 65: 73--146.
1. Homalotheciella subcapillata (Hedwig) Brotherus in H. G. A. Engler & K. A. E. Prantl, Nat. Pfl. 1(3): 1133. 1908
Pterigynandrum subcapillatum Hedwig, Sp. Musc. 83. 1801; Burnettia fabrofolia Grout; Homalotheciella fabrofolia (Grout) Brotherus; Homalothecium subcapillatum (Hedwig) Sullivant; Pterogonium decumbens Schwägrichen; Pterigynandrum brachycladon Palisot de Beauvois ex Bridel
Plants glossy. Stems regularly or irregularly pinnate, branches ascending-erect, straight or curved, 2 mm. Leaves erect, concave, 1 mm; margins erect, serrate-denticulate; apex slenderly acuminate; costa slender, ending at mid leaf, often weak or indistinct; medial cells elongate, 40--60 x 5 /um; alar cells quadrate in 2--5 vertical rows. Seta 5--10 mm. Capsule brown, mostly slightly asymmetric, smooth or wrinkled-plicate when dry, 1--1.5 mm; peristome pale, teeth 300 /um. Calyptra 2 mm. Spores 18--25 /um.
Spores mature September--February. Trunks of soft-barked trees, rarely on logs, roots, stumps, and rocks, mesic to wet forests; 0--1950 m; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Miss., Mo., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Tex., Va., W.Va.
Homalotheciella subcapillata is distinctive in its small glossy creeping pinnate plants bearing leaves with long slender tips crowded on short branches. Also, the nonplicate leaves with denticulate margins, weak costa, quadrate alar cells, and delicately-haired calyptra make the species easy to recognize. Among the Brachytheciaceae the calyptra is mostly naked and the leaves are often plicate. Plants of Pylaisiella selwynii (Hypnaceae) can be very similar to H. subcapillata at first glance, but differ in their more regularly curved branches and ecostate entire-margined leaves.