32. STREPTOPOGON Plates 41– 42.

Streptopogon Wils. in Mitt., Kew J. Bot. 3: 51, 1851. Type: Streptopogon erythrodontus (Tayl.) Wils.

Striptopogon Hampe, Flora 45: 450, 1862, orthogr. var.

Sect. Streptopogon

Sect. Streptopogon (Wils.) Mitt., Phil. Trans. R. Soc. London 168: 33, 1879, nom. superfl.

Streptopogon sect. Eustreptopogon C. Müll., Gen. Musc. Fr. 423, 1900, nom. illeg.

Sect. Calymperella C. Müll., Hedwigia 33: 128, 1894.

Sect. Streptopogonella Demar. & P. Varde, Bull. Jard. Bot. Bruxelles 26: 270, 1956. Type: Streptopogon calymperoides Demar. & P. Varde.

Plants growing in tufts or mats, green above, reddish brown below. Stems commonly branching, ca. 0.5–3.0 cm in length, transverse section rounded-pentagonal to elliptical, central strand absent (inner cells of central cylinder occasionally crushed), sclerodermis weakly developed to distinct, hyalodermis absent; axillary hairs of ca. 7–10 cells, basal 1–3 cells often brownish; often red-tomentose below. Leaves appressed-incurved to lax and weakly contorted when dry, widely spreading and recurved when moist, ovate-lanceolate, 2.0–6.5 mm in length, upper lamina keeled to broadly channeled, margins recurved to revolute at leaf base or to near apex, entire to denticulate or serrulate above, sometimes bordered with elongate cells below or throughout; apex acute to acuminate, occasionally rounded and cucullate; base scarcely differentiated to rectangular, somewhat decurrent; costa usually strongly bulging dorsally, percurrent to excurrent as a weakly denticulate awn, occasionally subpercurrent by several cells, superficial cells on both sides elongate and smooth, 2 rows of cells across costa ventrally at midleaf, costal transverse section round, stereid band single, usually strong and round to semicircular, ventral and dorsal epidermis present or occasionally absent, guide cells 2 in 1 layer, hydroid strand absent; upper laminal cells rectangular to rhombic, occasionally fusiform near apex leaf, 15–20 µm in width, 2(–3):1, walls thin to thick, occasionally porose, superficially equally convex on both sides of lamina; papillae absent; basal cells only weakly differentiated from the upper cells, rectangular, to 25 µm in width, 3–5:1, walls thin to weakly thickened and porose. Uni- or multiseriate (with internal longitudinal walls) elliptical propagula borne on dorsal leaf apex, apex of costa or upper leaf margins, seldom remaining on mature leaves, clavate or cylindrical, of 8–16 cells. Dioicous, paroicous, synoicous or autoicous. Perichaetia terminal, leaves somewhat enlarged, inner leaves long-elliptical to oblong, to 9.0 mm in length, not sheathing, lower cells thin-walled and rectangular in lower 3/4. Perigonia in dioicous species terminal on branches of much-branching smaller plants. Seta usually short, 0.5–9.0 mm in length, 1(–2) per perichaetium, yellowish, occasionally twisted clockwise; theca 3.0–3.5 mm in length, yellowish brown, elliptical, often with a short, rugose neck, mouth of theca occasionally flaring or forming a narrow ring, columella may protrude past mouth of theca after removal of operculum, exothecial cells rectangular, walls thin to weakly thickened, stomates phaneropore, at base of theca, annulus of ca. 4 rows of weakly vesiculose cells, persistent; peristome teeth 16–32 (reportedly absent in one species), often coming off with operculum, often strongly spreading when wet, twisted when dry, linear, filamentous, variously cleft, densely spiculose, ca. 1000–1400 µm, with several articulations, twisted counterclockwise ca. once, basal membrane 70–800 µm in height, densely spiculose. Operculum conic, ca. 0.9–2.0 mm in length, cells twisted counterclockwise ca. once. Calyptra conic-mitrate, lobed below, strongly papillose (prorulose) with upward pointing simple papillae (but reportedly smooth in three species), 2.0–3.0 mm in length. Spores ca. 13–15(–30) µm in diameter, light brown, densely papillose. Laminal KOH color reaction usually red, occasionally yellow to yellowish orange. Reported chromosome number n = 20.

Found on rocks and tree branches and trunks; Latin America, central and southern Africa, Madagascar and Hawaii.

Important characters for Streptopogon are the plant's reddish color below, lack of a central strand in the stem (Pl. 41, f. 2, 11), ovate-lanceolate leaves, costa with one stereid band and no hydroids (Pl. 41, f. 8; 42, f. 5, 14, 22), upper laminal cells smooth, basal cells little differentiated from the upper, clavate propagula often present on leaves or costa (Pl. 41, f. 14, 16, 19; 42, f. 17), perichaetial leaves not or little sheathing, seta often short (Pl. 41 1), calyptra usually scabrous-prorulose (Pl. 41, f. 9–10; 42, f. 9—as in Hypodontium), and laminal KOH reaction usually red. The peristome (Pl. 42, f. 7, 15) often is only weakly attached basally and may be removed with the operculum resulting in what appear to be gymnostomous capsules; however, Griffin (1979b) reported, from a collection with a single sporophyte with semidetached operculum and calyptra, what appears to be a true gymnostomous condition in S. calymperes. Crum (1952b) found both the synoicous and paroicous condition in a specimen of S. heterophyllus from southern Peru; the type of this species at W! is synoicous and autoicous. Streptopogon stenophyllus (Pl. 42, f. 18–22) and S. calymperoides are unique in their yellow to yellowish orange reaction to KOH; the former is, however, clearly a member of the genus, possessing characteristic weak costa, lack of a stem central strand, papillose long-mitrate calyptra, seta only slightly longer than the 2 mm-long capsule, and little-differentiated perichaetial leaves, while the latter, though known only from extremely fragmentary, sterile material, is much like S. calymperes. “Streptopogon peruvianus” (L!), although cited as a correct name in Index Muscorum (van der Wijk et al. 1959–1969) lacks a description, and is thus a nomen nudum.

Additional literature: Brown (1898a), Griffin (1986b), Salmon (1903), Sharp (1986).

Number of accepted species: 14.

Species examined: S. calymperes (NY), S. calymperoides (FH), S. cavifolius (TENN), S. clavipes (BUF), S. erythrodontus (NY), S. heterophyllus (L), S. matudianus (TENN), S. stenophyllus (PC).

New heterotypic synonymy: Streptopogon australis Mitt. = “Daltonia angustifolia? Dozy & Molk.” fide H. Robinson's annotation of the type (NY); the type is definitely assignable to that widely distributed species; also note the strong yellow KOH reaction.