41. HYOPHILA              Plates 54, 55 - 56.

Hyophila Brid., Bryol. Univ. 1(Suppl.): 760, 1827. Lectotype: Hyophila javanica (Nees & Blume) Brid. fide Hampe in Bot. Zeit. 4: 266, 1846.

Rottleria Brid., Bryol. Univ. 1: 105, 1826, hom. illeg. non Wild., 1797.

Hygrophila Syd., Bot. Jahresber. 39(1): 99, 1912, nom. inval. error pro Hyophila Brid.

Hyophila subg. Gymnohyophila Card. in Grand., Hist. Madag. 39: 208, 1915, nom. illeg. incl. type. gen.

Gymnostomum sect. Hyophila (Brid.) Reichenb., Consp. Regn. Veg. 1: 33, 1828.

Pottia sect. Hyophila (Brid.) C. Mόll., Syn. 1: 558, 1849.

Weissia sect. Hyophila (Brid.) Mitt., J. Linn. Soc. Bot. 12: 135, 1869.

 

Fromu,'w,to wet, rain + ji'loV,love, dear, beloved; referring to a preference for wet habitats.

            Plants turf-forming or occasionally loosely caespitose, green above, red to reddish brown or dark green below. Stems branching occasionally, to 1.0 cm in length, transverse section rounded-pentagonal or triangular, central strand usually strong, occasionally absent or central portion of stem hollow, central cylinder often of rather thick-walled cells grading into a sclerodermis, sclerodermis usually present, often strong, in several layers, hyalodermis absent or present (often only weakly differentiated); axillary hairs 6–10 cells in length, these all hyaline; radiculose. Leaves often rosulate, tubulose-twisted, incurved and occasionally contorted when dry, spreading, occasionally rather fragile when moist, commonly spathulate or ligulate, often ovate, oblong or elliptical, usually narrowed to the base, to 2.5 mm in length, upper lamina broadly channeled, shallowly grooved along costa, occasionally concave, margins plane to broadly incurved, occasionally narrowly recurved in lower 2/3, entire or denticulate to dentate in upper 1/4 or just at apex, apex broadly acute to rounded, rarely cucullate or emarginate; base not differentiated in shape or half-sheathing, occasionally weakly auricled; costa subpercurrent or percurrent, ending in an apiculus or occasionally a mucro, superficial cells ventrally quadrate or more commonly short-rectangular, often bulging, dorsally elongate, 2–6 rows of cells across costa ventrally at midleaf, costal transverse section semicircular, 2 stereid bands present, ventral and dorsal epidermis present, guide cells 4(–6) in 1 layer, hydroid strand occasionally present; upper laminal cells rounded-quadrate or hexagonal, usually small, 6–13 ΅m in width, 1:1, walls thin to evenly thickened, either superficially ventrally strongly bulging and dorsally weakly convex, or bulging equally on both sides; papillae absent or simple, solid, often only on dorsal surface of lamina, occasionally weakly bifid; basal cells differentiated across leaf or medially, usually restricted to small area near insertion, short-rectangular, 10–20 ΅m in width, 1–4:1, walls thin to evenly thickened. Propagula often present, clavate, stellate or dentate-elliptical, often to 300 ΅m in length, borne on stout, branching stalks in leaf axils. Dioicous or monoicous (autoicous, paroicous). Perichaetia terminal and inner leaves little different from or smaller than the cauline, half-sheathing, lower cells thin-walled and rhomboidal in lower half. Perigonia as lateral buds on perichaetiate plants or terminal on perigoniate plants, inner leaves little differentiated. Seta 0.4–0.7 cm in length, 1(–2) per perichaetium, reddish to yellowish brown, twisted clockwise; theca 1.0–2.3 mm in length, reddish to yellowish brown, long-ovoid to cylindrical, exothecial cells quadrate to rectangular, 20–45 ΅m in width, 1–5:1, walls thin or much thickened both on exposed and contiguous sides, stomates phaneropore, at base of theca, annulus 1–3 rows of vesiculose cells, deciduous in pieces or persistent on theca or operculum; peristome teeth absent. Operculum conic to long-conic or rostrate, 0.5–0.8 mm in length, cells not twisted. Calyptra cucullate, often twisted about the seta when mature, smooth, 2–3 mm in length. Spores 7–24 ΅m in diameter, light brown, papillose. Laminal KOH color reaction yellow, occasionally with a red blush medially above midleaf, occasionally cells near leaf insertion red. Reported chromosome number n = 7, 13, 13+m.

            Found on rock, soil and trees, generally in moist or wet areas, throughout the tropic and temperate zones.

            Abundant synonymy and combinations in other genera will certainly be necessary on revision for presently accepted correct names in Hyophila. Recent synonymy by various authors includes several broad-leaved sterile or eperistomate taxa in Hyophila transferred to or synonymized with species in such genera as Barbula, Didymodon, Bryoerythrophyllum, Gymnostomum, Gyroweisia, Plaubelia, Scopelophila, Tortula, Trichostomum and Weissia. Many correct names in Hyophila provisionally accepted during this study are based on type or authentic specimens expected, on revision, to prove to be H. involuta (Pl. 54, f. 1–11); this species requires comprehensive evaluation, however, and extensive synonymy within the genus was not attempted. The species illustrated here are mostly those fairly different from H. involuta.

            Many species of the genus are morphologically similar to Trichostomum; these seem to intergrade with Trichostomum species through such similar, intermediate taxa as Plaubelia, Hyophila nymaniana (Pl. 55, f. 18–25) and T. planifolium. Trichostomum itself certainly shows tendencies towards the Hyophila morphotype (e.g. Magill 1981, p. 262 refers Hyophila zeyheri of South Africa to the synonymy of Trichostomum brachydontium because of peristome variation from rudimentary to absent, see also Sιrgio 1985). The upper laminal cells ventrally bulging and dorsally flattened are developed only medially in H. bartramiana and H. subcucullata (Pl. 56, f. 6–10), two closely related monoicous species that also have laminal papillae. Ventrally bulging upper laminal cells (usually also ornamented with papillae) are also found in many species of Weissia, but Weissia is apparently not closely related to Trichostomum (see Cladogram 14 and others) on analysis using the full character set, although it is related to Hyophila. Hyophila appears to be a weakly segregated end point of a parallelline of evolution towards Trichostomum species (sect. Laminanchium) with ventrally bulging upper laminal cells, or else the latter is better seen as a separate taxon at the genus level in the Hyophileae or even transferred to Hyophila.

            Some species of Hyophila, including the generitype, H. involuta, have certain of the characters of Barbula (Norris and Koponen 1989 felt that Hyophila is closely related to Barbula) including recurved lower laminal margins, medially differentiated basal laminal cells, ventrally colliculate but dorsally smooth upper lamina (e.g. B. javanica) and armed, often caltrop-shaped propagula (as in Barbula indica and Barbula sect. Hydrogonium). Also, the capsules of some species (e.g., H. involuta and H. nymaniana) are large, dark brown and thick-walled, reminiscent of capsules of Barbula or Tortula, while others (e.g., H. acutifolia) are short, yellowish and thin-walled, like those of Trichostomum or Weissia; intermediates are few. These features indicate that Hyophila as presently recognized is polyphyletic. Of some significance is that H. siamensis (Pl. 56, f. 1–5) could be placed with Barbula by its narrowly recurved marginal laminal cells and other characters, except that the spathulate leaf shape and lack of a peristome at the present time militate against it; the same is true for H. nymaniana, which differs widely from other Hyophila species in the presence of punctate papillae (curiously like those of certain species of Rhachitheciaceae) on the upper laminal cells, which bulge on both sides of the leaf, the absence of a stem central strand, and the bright red KOH color reaction of the basal laminal cells at the leaf insertion (the la

st two characters are unusual but duplicated in Leptodontium viticulosoides and Tortula cuneifolia var. blissii). On the other hand, H. apiculata (Pl. 55, f. 1–5) appears to be a phenocopy of B. agraria in the short-ovate leaf shape, acute apex and sharply excurrent costa. Additional study is needed for satisfactory disposition of these Hyophila species.

            Distinctive characters often but not always found in Hyophila species in various combinations and which must serve to distinguish Hyophila from Trichostomum and Barbula include: leaves ligulate, narrowed to the insertion, broadly concave in transverse section; upper laminal cell surfaces epapillose, ventrally bulging and dorsally weakly convex (Pl. 54, f. 7); basal laminal cells short and poorly differentiated or differentiated cells restricted to a small area near the insertion; propagula present, armed (Pl. 54, f. 8; 55, f. 23); monoicous; capsule eperistomate, and exothecial cells thick-walled (Pl. 55, f. 25). No species of Hyophila has all these characters and few have most. Hyophila differs from Plaubelia mainly in being eperistomate and the ventral surface of the costa usually consisting of elongate cells. The leaf hydroid strand is also often absent in Hyophila, but these characters may ultimately prove insufficient to separate the two taxa at the generic level. Two species previously placed in Hyophila probably because of their lingulate leaves and eperistomate capsules are here referred to Tisserantiella of the Rhachitheciaceae (one as a synonym, the second as a comb. nov., see Excluded Taxa) because their costa mostly end below the leaf apex and the upper laminal papillae are extremely small, solid, punctiform to short-spiculose, with the appearance of tiny specks of light under the compound lens (these characters are unique only in combination).

            Additional literature: Andrews and Redfearn (1965), Deguchi et al. (1991), Gao et al. (1991), Long (1978), Mehra (1984, 1988), Nawawi and Mohamed (1989), Olarinmoye (1981), Rahbar and Chopra (1980), Sakurai (1954), Sharma and Chopra (1986), Sharp (1955), Smith and Whitehouse (1974), Yang (1965).

            Number of accepted species: 88.

            Species examined: H. acutifolia (TNS), H. apiculata (FH), H. bartramiana (BUF, MICH, TENN), H. beruensis (H), H. blanda (NY), H. grossidens (H), H. involuta, H. latifolia (H), H. mattogrossensis (H), H. nymaniana (BUF, NY, TENN), H. potierii (FH), H. propagulifera (H, NY, TNS), H. siamensis (BM), H. spathulata (NY), H. subcucullata (NY), H. subflaccida (NY), H. usambarica (H), H. viridula (BUF).

            New heterotypic synonymy: Gymnostomum denticulatum Griff. (NY) = Hyophila involuta (Hook.) Jaeg.