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Published In: Bryologia Universa 1: 522. 1826. (Bryol. Univ.) Name publication detailView in Biodiversity Heritage Library

Project Name Data (Last Modified On 11/3/2011)
Acceptance : Accepted
Project data     (Last Modified On 11/3/2011)

42. PLAUBELIA                   Plate 57.

Plaubelia Brid., Bryol. Univ. 1: 522, 1826 (nom. rejic. vs. Trichostomum Bruch, 1829). Type: Plaubelia tortuosa Brid.

Hyophilopsis Crum, Bryologist 68: 69, 1965, non Card. & Dix. 1911, hom. illeg.

Neohyophila Crum, Bryologist 68: 470, 1965, nom. nov. for Hyophilopsis Crum, hom. illeg. Type: Neohyophila sprengelii (Schwaegr.) Crum.

Tortula sect. Plaubelia (Brid.) Mitt., J. Linn. Soc. Bot. 143, 154, 1869.


            Found on rock, soil, especially calcareous substrates, in extreme southwestern and southeastern U.S.A., Mexico, Central America, the West Indies, Venezuela, Brazil, South Africa and Burma.


            Bridel (1826–27) established Plaubelia to include the single species Plaubelia tortuosa Brid. (= Desmatodon sprengelii (Schwaegr.) Williams, a taxonomic synonym fide Williams 1919). The name Plaubelia fell from use after being rejected against the later (1829) generic name Trichostomum Bruch; M. Crosby (in litt.) noted that Plaubelia is acceptable when it is not a taxonomic synonym of Trichostomum Bruch. Crum (1965a) created Hyophilopsis (and later the nomen novum Neohyophila, a heterotypic synonymn of Plaubelia) as a segregate of Desmatodon, citing, as a unique combination of features, the spathulate, rosulate leaves (Pl. 57, f. 1, 9, 10) with erect or incurved margins, laminal cells ventrally bulging, and the ventral epidermis of bulging cells (Pl. 57, f. 5). He further referred the genus to the Pottioideae, citing a single stereid band, but I agree with Delgadillo and Crdenas (1982) that this character is variable, as one or two bands may be present in different leaves of the same plant. Actually Plaubelia is apparently most closely related to Hyophila, from which it differs most saliently in the presence of a peristome (Pl. 57, f. 8, 18). The strongly involute margins are reminiscent of Weissia. The presence of a hydroid strand (Pl. 57, f. 7, 16) and of rounded-quadrate ventral epidermal cells (as seen from above) on the costa are also good characters distinguishing Plaubelia from the similar and very commonly distributed Hyophila involuta, as well as several other Hyophila species but not all (Hyophila greatly needs revision). Globulinella is very similar in many respects, but is distinguishable by the costa not bulging dorsally and the usually cucullate leaf apex. Crum and Anderson (1981) placed the species Merceyopsis angulosa with Plaubelia (without actually making a combination), but that species is better viewed as the monotypic genus, Ganguleea ((q.v.).

            Two new combinations are here added to Plaubelia from the Old World, where they were previously recognized in Desmatodon and Weisiopsis. These additional species differ from the American P. sprengelii in their strongly involute upper laminal margins. They are otherwise little different from each other and may prove synonymous.

Literature: Crum (1965c), Delgadillo & Zander (1985), Saito (1973d), Zander (1983c).
Number of accepted species: 3
Species Examined: P. involuta (NY), P. perinvoluta (FH), P. sprengelii.


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Plants forming turf or loosely caespitose, green above, green or sometimes brown below. Stems often branching, to 4 mm in length, in transverse section rounded-pentagonal, central strand strong, sclerodermis present, often weak, hyalodermis absent; axillary hairs of up to 5 uniseriate cells, the basal 1–2 yellow; rhizoids sparse. Leaves incurved to spreading, often tubulose when dry, widely spreading when moist, usually rosulate, spathulate to oblong, to 3.2 mm in length, ventral surface flat to broadly concave across leaf; margins incurved, involute, or occasionally plane, sometimes broadly involute at the apex, entire to distantly denticulate above; apex rounded acute to broadly obtuse, apiculate or occasionally entire; base little differentiated in shape; costa percurrent or ending up to 4 cells below the apex, adaxial surface cells bulging, rounded-hexagonal, ca. 4 rows of cells across ventral surface of costa at midleaf, dorsal cells elongate, costa in transverse section rounded, showing one or two stereid bands, the dorsal semicircular in section except for a ventral indentation at the hydroid strand, ventral epidermis differentiated, 2–4 guide cells in 1 layer, dorsal epidermis slightly differentiated, hydroid strand present (this occasionally difficult to demonstrate in small plants); upper laminal cells rounded-hexagonal, 8–10 µm in width, 1:1, walls evenly thickened, ventrally strongly convex and dorsally nearly flat; upper laminal papillae often absent, when present solid, small, simple, 1–2 per lumen dorsally or occasionally present on both sides of lamina; basal cells not differentiated or often forming a small group medially or weakly differentiated across the leaf, quadrate to short-rectangular, to 15 µm wide, 2–3:1, hyaline to somewhat yellowish; 1–2 rows of inflated, hyaline cells across insertion sometimes also present, occasionally forming small auricles. Propagula in leaf axils, clavate, often multi-branched at the wider end, mostly 100–300 µm in length, with occasional internal walls. Dioicous. Perichaetia terminal, inner leaves ovate-lanceolate to ligulate, slightly larger or somewhat shorter than outer leaves, weakly or strongly sheathing, cells long-rhomboidal or rectangular in lower half. Perigonia terminal, inner leaves ovate, outer leaves large. Seta to 0.8 cm in length, yellow- to red-brown, twisted clockwise below, often counterclockwise above, 1 per perichaetium; theca ca. 1.0–1.5 mm in length, red- or yellow-brown, ellipsoidal or oblong, exothecial cells somewhat bulging, rectangular, ca. 15–35 µm in width, 2–5:1, walls thin to weakly porose and thickened, stomates phaneropore, present at base of capsule above a comparatively well developed neck; annulus of strongly vesiculose cells, persistent on the capsule mouth, detaching in pieces or revoluble; peristome of 16 spiculose, lanceolate to long-linear teeth, cleft to near base or variously cleft or perforate, often only perforate at base and entire, to 180 µm in length, up to 9 articulations, straight, low-spiculose, basal membrane absent or to 25 µm in height, low-spiculose. Operculum rostrate, to 0.9 mm in length, cells in straight rows. Calyptra cucullate, smooth, 0.6–2.0 mm in length. Spores yellow, weakly papillose, small, ca. 8–10 µm in diameter. Laminal KOH color reaction yellow in upper leaves, often orange-brown in lower.
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