Hildebrandtiella guyanensis (Mont.) W.R.Buck

Authority

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

Family

Pterobryaceae

Scientific Name

Hildebrandtiella guyanensis (Mont.) W.R.Buck

Description

Species Description - Plants medium-sized, the secondary stems to ca. 8 cm, but often 3-5 cm long, in green to yellow-green, mostly thin mats. Primary stems creeping, often short, mostly tightly adherent to substrate and usually lacking in herbarium specimens, filiform, with small, reduced leaves, turning ca. 90° and becoming the upright secondary stem (stipe), the creeping stem continuing by a bud from near the base of the stipe, secondary stems erect to pendent, irregularly pinnately branched, the branches mostly simple, not complanate-foliate; in cross-section with 3-5 rows of small thick-walled cells surrounding larger firm-walled cells, central strand none; paraphyllia none; pseudoparaphyllia filamentous, numerous; axillary hairs with a single short brown basal cell and 2 elongate hyaline distal cells. Secondary stem and branch leaves in 5 obvious spiral rows, especially conspicuous when moist, spreading, oblong-ovate, 1.5-2 mm long, appearing ± cuspidate, strongly concave, cordate at base, very shortly decurrent; margins subentire throughout or with a few small teeth at the extreme apex, strongly incurved above, plane below; costa mostly absent; cells linear-subflexuose, smooth, firm- to thick-walled, porose; alar cells very few or rarely (on leaves from the same stem) with a well-marked but small alar region, subquadrate, firm-walled, not or scarcely porose, yellow. Asexual propagula of gemmae clustered in leaf axils, uniseriate, ca. 10-20-celled, relatively large, to 225 µm long, golden. Dioicous. Perichaetia large, conspicuous; leaves strongly differentiated, erect, convolute, oblong-lanceolate, to ca. 4.3 mm long, gradually long-acuminate; margins entire to subentire, plane; costa none; cells linear-flexuose, smooth, firm- to thick-walled, porose, becoming rectangular in 3-5 rows across the yellowed insertion. Setae short, smooth, ca. 0.6 mm long; capsules immersed, erect and symmetric, broadly cylindric, ca. 2 mm long; exothecial cells subquadrate, firm-walled, becoming oblate at the mouth; annulus not differentiated; operculum conic-rostrate, ca. 0.7 mm long, somewhat oblique; peristome double, inserted below the mouth, exostome teeth pale, yellow, narrowly triangular, unornamented, usually with a well-developed prostome; endostome rudimentary, with a low basal membrane and short segments. Spores spherical to oblong, finely roughened, 20-29 µm diam. Calyptrae mitrate, naked, smooth.

Discussion

1. Hildebrandtiella guyanensis (Mont.) W. R. Buck, Brittonia 43: 97. 1991; Neckera guyanensis Mont., Syll. Gen. Sp. Crypt. 24. 1856; Meteorium guyanense (Mont.) Mitt., J. Linn. Soc., Bot. 12: 430. 1869, “guianense”; Pilotrichella guyanensis (Mont.) Paris, Index Bryol. 945. 1895; Orthostichidium guyanense (Mont.) Broth. in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 795. 1906. Plate 60, figures 8-15 Meteorium excavatum Mitt., J. Linn. Soc., Bot. 12: 430. Jun 1869; Pilotrichella excavata (Mitt.) A. Jaeger, Ber. Thátigk. St. Gallischen Naturwiss. Ges. 187576: 254. 1877; Orthostichidium excavatum (Mitt.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 795. 1906. Pilotrichum pentagonum Hampe & Lorentz in Hampe, Bot. Zeitung (Berlin) 27: 449. 9 Jul 1869; Pilotrichella pentagona (Hampe & Lorentz) A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1875-76: 257. 1877; Orthostichidium pentagonum (Hampe & Lorentz) Midl. Hal., Bull. Herb. Boissier 5: 205. 1897; Hildebrandtiella pentagona (Hampe & Lorentz) Paris, Index Bryol. Suppl. 181. 1900. Discussion. Hildebrandtiella guyanensis is locally distinguished by the seriately arranged, oblong-ovate, ecostate leaves with strongly incurved margins and poor alar development. It is differentiated from Orthostichopsis tetragono by the ecostate leaves. It might be confused with species of Pilotrichella because of the leaf shape, lack of a costa, and incurved margins, but Pilotrichella has monopodial branching, lacks filamentous pseudoparaphyllia, and has a small but distinct group of alar cells. The setae are more elongate in Pilotrichella and thus result in exserted capsules. I have not seen the type of Neckera guyanensis Mont, but am relying on Florschütz (1964: 247) and photographs of the type in NY (from PC). West African material is very similar to our American collections. In fact, the leaves are inseparable. However, from the limited specimens I have had at my disposal from Africa, there is a slight aspect difference. Since the African name (Meteorium involutifolium Mitt., 1868) is considerably younger than the American one, I have not felt compelled to pursue it since it cannot displace our name.

Distribution

Range. Mexico to Costa Rica, northern Andean South America, Brazil, Paraguay, French Guiana, ? west tropical Africa (see discussion below); Cuba, Jamaica, Hispaniola (Haiti and Dominican Republic), Puerto Rico; mostly growing on tree trunks and branches, sometimes in the canopy, in humid forests, at 500-1500 m.

Mexico North America| Belize Central America| Guatemala Central America| El Salvador Central America| Honduras Central America| Costa Rica South America| Nicaragua Central America| Venezuela South America| Colombia South America| Ecuador South America| Peru South America| Bolivia South America| Brazil South America| Paraguay South America| French Guiana South America| Africa| Cuba South America| Jamaica South America| Haiti South America| Dominican Republic South America| Puerto Rico South America|