Sematophyllum

• Authority

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

• Family

  Sematophyllaceae

• Scientific Name

  Sematophyllum

• Description

  Genus Description - Plants small to robust, in mostly lustrous, ± yellow-green, often dense, extensive mats. Stems creeping, sparsely to freely but irregularly branched, the branches prostrate to erect, densely foliate, often curved; in cross-section with small thick-walled colored cells surrounding larger thinner-walled cells, central strand absent; pseudoparaphyllia foliose, small; axillary hairs with 1-2 usually rectangular brown basal cells and 1-3(-5) elongate hyaline distal cells. Stem and branch leaves similar, erect-spreading to homomallous to falcate-secund, lanceolate to ovate, acute to acuminate, rarely obtuse, usually concave; margins entire to serrulate above, subentire below, often reflexed; costa short and double or absent; cells rhomboidal to linear, sometimes flexuose, smooth or rarely unipapillose, often thick-walled, mostly not or only weakly porose, often becoming shorter in the apex if acute; alar cells enlarged and inflated, often in 2 rows in basal angles, usually yellow, the lower ones mostly oblong, the upper ones usually quadrate. Asexual propagula rare. Mostly autoicous. Perichaetial leaves erect, lanceolate to ovate, acute to acuminate; margins usually entire, plane; costa mostly none; cells linear to linear-flexuose, smooth, often thick-walled and porose, becoming shorter, broader, thinner-walled and yellow toward the insertion; alar cells not differentiated. Setae elongate, smooth, usually reddish; capsules mostly pendent, rarely erect to suberect, small, usually ± asymmetric, ovoid to short-cylindric, rarely with a roughened neck; exothecial cells mostly subquadrate, collenchymatous; annulus not differentiated; operculum mostly obliquely and slenderly long-rostrate; peristome double, exostome teeth triangular, strongly shouldered, strongly 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 usually papillose, mostly broad, keeled, often perforate, almost as long as the teeth, cilia in groups of 0-2. Spores spherical, finely papillose. Calyptrae cucullate, naked, usually smooth.

• Discussion

  Sematophyllum Mitt., J. Linn. Soc., Bot. 8: 5. 1864; Hypnum sect. Sematophyllum (Mitt.) Angstr., Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 30(5): 149. 1873. Hypnum sect. Mallacodium subsect. Aptychus Müll. Hal., Syn. Musc. Frond. 2: 325. 1851; Aptychus (Müll. Hal.) Müll. Hal., Flora 82: 471. 1896; Rhaphidostegium sect. Aptychus (Müll. Hal.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1111. 1908. Rhynchostegium sect. Rhaphidostegium Bruch & Schimp. in Bruch, Schimp. & W. Gümbel, Bryol. Eur. 5(fasc. 4951, Monogr. 7): 200. 1852; Hypnum sect. Rhaphidostegium (Bruch & Schimp.) Sull. in A. Gray, Manual, ed. 2, 670. 1856; Rhaphidostegium (Bruch & Schimp.) De Not., Comment. Soc. Crittogam. Ital. 2: 297 [reprinted as Cronaca Briol. Ital. 2: 31]. 1867; Hypnum subgen. Rhaphidostegium (Bruch & Schimp.) Lesq. & James, Man. 317, 355. 1884. Microcalpe Spruce, Cat. Musc. 13. 1867, nom. nud.; Sematophyllum sect. Microcalpe Mitt., J. Linn. Soc., Bot. 12: 477, 494. 1869; Rhaphidostegium sect. Microcalpe (Mitt.) Besch., Ann. Sci. Nat. Bot. VI, 3: 254. 1876. Rhaphidorrhynchium Besch., Compt. Rend. Hebd. Séances Acad. Sci. 81: 721, 723. 1875, nom. nud., M. Fleisch., Musci Buitenzorg 4: 1245. 1923. Pungentella Müll. Hal., Nuovo Giorn. Bot. Ital. II, 4: 152. 1897, non Flora 82: 470. 1896, nom. nud. [= Acroporium Mitt.]. Meiothecium sect. Pseudo-Meiothecium Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1101. 1908. Discussion. I have used a broad generic concept in Sematophyllum. The separation of Pungentella (= Rhaphidorrhynchium) seems to do nothing more than create another polyphyletic genus. Fleischer (1923) solidified modem usage of the genera of Sematophyllaceae. Sematophyllum s.str. was based on nothing more than leaves more or less erect or sometimes homomallous as opposed to falcate and homomallous. Pungentella was separated from Rhaphidostichum by delicate plants with gradually acuminate leaves in the former and robust plants with abruptly acuminate leaves in the latter. However, the roughened upper seta and capsule neck, and furrowed exostome teeth in some species of Rhaphidostichum seem to have significance and I have chosen to recognize that genus. Pungentella was first used by Müller (1896: 470) without a generic description for four Hawaiian species. The following year he (Müller, 1897a: 152) described a single species of the genus in the Bolivian flora, thereby providing a combined generic and specific description. Because of that single Bolivian species (P. levieri Müll. Hal.), Rhaphidorrhynchium has been relegated to synonymy under Pungentella because the species was placed in Rhaphidorrhynchium by Brotherus (1925: 428). Of the original four Pungentella species, two have been placed in Acroporium and two in Trichosteleum. Sematophyllum is scarcely more than the dregs of the Sematophyllaceae. It is characterized by the lack of various specialized features. It has nonpapillose laminai cells, nonfurrowed exostome teeth, mostly nonerect capsules with little or no endostomial reduction, and exothecial cells not thin-walled. Generic problems in the family are great, and I have not comprehensively surveyed the extralimital genera.