Trichosteleum subdemissum (Besch.) A.Jaeger

  • Authority

    Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.

  • Family

    Sematophyllaceae

  • Scientific Name

    Trichosteleum subdemissum (Besch.) A.Jaeger

  • Description

    Species Description - Plants medium-sized, in somewhat lustrous, ± soft, golden-green to yellow-brown, lax, often extensive mats. Stems creeping, to ca. 3 cm long, reddish, freely but irregularly branched, the branches usually short, obscurely complanate-foliate; in crosssection with 2-3 rows of small thick-walled colored cells surrounding large firm-walled cells, central strand absent; pseudopa-raphyllia seemingly none; axillary hairs with a single short brown basal cell and (1-)2 elongate hyaline distal cells. Stem and branch leaves similar, erect-spreading, broadly ovate-lanceolate, 0.75-1.05 X 0.25-0.4 mm, acute, deeply concave; margins subentire to serrulate throughout, plane or occasionally recurved; costa very short and double or absent; cells linear, unipapillose in upper 2/3 of leaf, thin-walled, becoming rhombic toward the apex, becoming thicker-walled and porose toward the insertion, the papillae over most but not all cells, low but usually conspicuous, narrower in diameter than the lumina width; alar cells greatly enlarged and inflated, oblong, lightly colored, 2-3 at each basal angle. Asexual propagula none. Autoicous. Perichaetial leaves erect, lanceolate, 0.65-0.82 mm long, acuminate; margins serrate above, subentire below, plane; costa mostly none; cells linear, smooth, firm- to thick-walled, ± porose, becoming laxly rectangular toward the insertion; alar cells not differentiated. Setae elongate, smooth, reddish, ca. 0.8 cm long, curved just below the urn; capsules inclined to pendent, small, asymmetric, ovoid-cylindric, 0.7-0.9 mm long; exothecial cells subquadrate, strongly collenchymatous, becoming smaller, oblate, and evenly thin-walled in 1-2 rows at the mouth; annulus not differentiated; operculum obliquely long-rostrate, longer than the urn; exostome teeth narrowly triangular, shouldered, bordered, on the front surface with a zig-zag median line, cross-striolate below, coarsely papillose above, trabeculate at back; endostome with a high basal membrane, segments papillose, broad, keeled, perforate, almost as long as the teeth, cilia single. Spores spherical, papillose, 12.5-15 µm diam. Calyptrae cucullate, naked, roughened above.

  • Discussion

    6. Trichosteleum subdemissum (Besch.) A. Jaeger, Ber. Thátigk. St. Gallischen Naturwiss. Ges. 1876-77: 418. 1878; Rhaphidostegium subdemissum Schimp. ex Besch., Ann. Sci. Nat. Bot. VI, 3: 250. 1876. Plate 140, figures 1-7 Hypnum microcarpum Homsch. in Mart., Fl. Bras. 1(2): 84. 1840, hom. illeg., non Hypnum microcarpon Hedw., Sp. Musc. Frond. 244. 1801 [= Distichophyllum microcarpon (Hedw.) Mitt.], nec Hypnum microcarpum Hook., Icon. Pl. 1: 23. 1837 [1836], hom. illeg. [= Trichosteleum brachypelma (Müll. Hal.) Paris], nec Hypnum microcarpum (Brid.) Müll. Hal., Syn. Musc. Frond. 2: 326. 1851, hom. illeg. [= Sematophyllum adnatum (Michx.) E. Britton]; Hypnum hornschuchii Hampe, Icon. Musc. 9 (adnot.). 1844 [7 1845], nom. nov., hom. illeg., non Dozy & Molk., Ann. Sci. Nat. Bot. Ill, 2: 307. 1844 [= Wijkia hornschuchii (Dozy & Molk.) H. A. Crum]; Trichosteleum hornschuchii A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1876-77: 418. 1878, non Trichosteleum microcarpum (Mitt.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1119. 1908. Hypnum martianum Lorentz, Moosstudien 166. 1864, hom. illeg., non Sendtn., Denkschr. Bayer. Bot. Ges. Regensburg 3: 150. 1841 [= Cyrto-hypnum minutulum (Hedw.) W. R. Buck & H. A. Crum]; Hypnum martii Lorentz ex Müll. Hal., Linnaea 39: 466. 1875, orthogr. var.; Trichosteleum martianum A. Jaeger, Ber. Thátigk. St. Gallischen Naturwiss. Ges. 1876-77: 419. 1878; Trichosteleum martii (Müll. Hal.) Kindb., Enum. Bryin. Exot. 38. 1888, comb. superfl. Discussion. Trichosteleum subdemissum is easily recognized by its acute leaves with the apical cells shorter than the median ones. The leaves are also more concave than those of the other Antillean species of the genus. Trichosteleum subdemissum has most often been called T. ambiguum (Schwãgr.) Paris, of northern South America. However, examination of the type in Geneva indicates that the species is not even in the Sematophyllaceae and should be in the Brachytheciaceae as Rhynchostegium ambiguum (Schwãgr.) W. R. Buck. comb. now [Leskea ambigua Schwägr., Sp. Musc. Frond. Suppl. 2(2): 165. 1827], For a small, seldom collected moss, Trichosteleum subdemissum has a complicated synonymy. The oldest name for the moss, described by Hornschuch (1840) in Flora Brasiliensis, is Hypnum microcarpum Homsch. Hampe (1844), recognizing that the Hornschuch name was a homonym, offered H. hornschuchii as an alternative. That nomen novum, though, is also a homonym, of a moss from Java, named just prior to it. By the time the epithet hornschuchii was moved to Trichosteleum, and was thus available for use, it had been preempted by Bescherelle’s Rhaphidostegium subdemissum, published two years earlier. Next, Lorentz (1864) published Hypnum martianum, but it also was a homonym. Later in a discussion of Trichosteleum, Müller (1875: 465-166) listed H. martii Lorentz. Although some authors have used this as a nomen novum for the homonymic H. martianum, there is no evidence for this assumption. Rather, it is most reasonable to think Müller’s name was only an orthographic error. By the time Jaeger (1878) validated use of the epithet martianum, Rhaphidostegium subdemissum had already been published.

  • Distribution

    Range. Brazil, the Guianas, west tropical Africa (Ivory Coast); Cuba (Isle of Pines), Hispaniola (Dominican Republic), Guadeloupe, Dominica, St. Vincent; mostly growing on old wood, sometimes on soil, in fairly open mesic forests and stream banks, from near sea level to 600 m.

    Brazil South America| Guyana South America| Suriname South America| French Guiana South America| Venezuela South America| Côte d’Ivoire Africa| Cuba South America| Dominican Republic South America| Guadeloupe South America| Dominica South America| Saint Vincent and the Grenadines South America|