Palamocladium leskeoides (Hook.) E.Britton

Authority

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

Family

Brachytheciaceae

Scientific Name

Palamocladium leskeoides (Hook.) E.Britton

Description

Species Description - Plants medium-sized, occasionally larger or smaller, in ± lustrous, soft, bright-green to golden, mostly dense mats. Stems creeping to ± ascending, irregularly to subpinnately branched, the branches usually ascending; in cross-section with 2-5 rows of small thick-walled cells surrounding larger firm-walled cells, central strand well developed, of very small cells with thin nodose walls; paraphyllia none; pseudoparaphyllia broadly foliose; axillary hairs with (1-)2 short brown basal cells and 1-3 elongate mostly brown and roughened (at least with age) distal cells. Stem and branch leaves similar but stem leaves ± ovate-triangular and 2.8-3.2 mm long, branch leaves erect-spreading, lanceolate to lanceolate-triangular, 1.8-2.6 mm long, gradually broadly long-acuminate, plicate, rounded to the insertion, often subauriculate; margins serrate above, serrulate below, mostly plane, sometimes erect; costa single, ending in the acumen, often subpercurrent, sometimes shorter; cells long-hexagonal to oblong-linear, subflex-uose, smooth, firm- to thick-walled, ± porose, becoming shorter in the acumen, becoming thicker-walled and more strongly porose toward the insertion; alar cells ± abruptly differentiated, often in excavate groups, mostly confined to the area near the insertion, not reaching the costa, often with a small band of nondifferentiated cells separating alar cells from the margin in the "auricle," quadrate to short-rectangular, firm- to thick-walled, ± porose. Asexual propagula none. Phyllodioicous. Perichaetia inconspicuous; leaves ± erect, oblong-ovate, 2.2-3.1 mm long, abruptly tapered to a long, slenderly loriform acumen, striate; margins serrate to serrulate above, mostly entire below, plane to erect; costa single, usually ending at base of acumen, occasionally longer; cells long-hexagonal to linear, sometimes subflexuose, smooth, thick-walled, mostly porose, becoming broader and long-rectangular toward the insertion; alar cells not differentiated. Setae elongate, smooth, reddish below, yellowish above, 1.5-3 cm long, slightly twisted; capsules erect, symmetric, long-cylindric with a slightly differentiated short neck, 2-3 mm long, smooth; exothecial cells short-rectangular, firm- to thick-walled, stomata round-pored; annulus of 2-3 rows of thick-walled rectangular cells, scarcely larger than those at mouth of urn, partially remaining attached to the operculum; operculum ± obliquely long-rostrate, the rostrum often fragile; exostome teeth reddish brown, triangular, ± shouldered, narrowly bordered, on the front surface cross-striolate below, with sparse overlying papillae, becoming irregularly striolate/papillose at midtooth, finely spiculose above, not or only slightly trabeculate at back; endostome densely but finely papillose, with a high basal membrane, segments narrow, keeled, not perforate, shorter than the teeth, cilia rudimentary or none. Spores spherical, finely papillose, 15-20 µm diam. Calyptrae cucullate, naked, smooth.

Discussion

1. Palamocladium leskeoides (Hook.) E. Britton, Bull. Torrey Bot. Club 40: 673. 1913 [1914]; Hookeria leskeoides Hook., Musci Exot. 1: 55. 1818; Leskea bonplandii Hook., Musci Exot. 2: 18. 1819, nom. illeg.; Hvpnum bonplandii (Hook.) Arn., Mém. Soc. Linn. Paris 5: 313. 1826, nom. illeg.; Homalothecium bonplandii (Hook.) A. Jaeger, Ber. Thätigk. St. Gallischen Natur-wiss. Ges. 1876-77: 311. 1878, nom. illeg.; Pleuropus bonplandii (Hook.) Broth, in Engl. & Prantl, Nat. Pflan-zenfam. 1(3): 1138. 1908, nom. illeg.; Isothecium bonplandii Renauld & Cardot ex E. Britton, Bull. Torrey Bot. Club 40: 673. 1913 [1914], nom. nud. in syn.; Pleuropus leskeoides (Hook.) Steere, Bryologist 51: 148. 1948; Homalothecium leskeoides (Hook.) H. Rob., Bryologist 65: 99. 1962. Plate 92, figures 10-17 lsothecium bonplandii var. haitense Renauld & Cardot ex E. Britton, Bull. Torrey Bot. Club 40: 673. 1913 [1914], nom. nud. in syn. Discussion. Palamocladium leskeoides has lanceolate branch leaves with margins serrate-serrulate throughout, a single costa, usually ending just short of the long-acuminate apex, and well-differentiated alar cells. At higher elevations of Hispaniola it is one of the most common non-epiphytic pleurocarps. There may be some superficial confusion with Hemiragis aurea, but that taxon has a strong double costa and lacks alar differentiation. Robinson (1962) suggested that P. leskeoides and P nilgheriense (Mont.) Müll. Hal. of India and East Asia may be synonymous. Indeed, the two are strikingly similar. I have not critically examined Asian material, since P leskeoides is the older name, but it seems to be a slightly smaller plant with shorter, thinner-walled cells in the leaf acumen. Most recently, Hofmann (1997) synonymized not only the Asian P nilgheriense with American P leskeoides but also the African P sericeum (A. Jaeger) Broth, as well as many other names based on Old World types. The above range reflects this synonymy.

Distribution

Range. United States (Appalachians, Texas, Oklahoma), Mexico to northern Andean South America, southeastern Brazil, northeastern Argentina, eastern and southern Africa, Madagascar, India, southeastern and eastern Asia, New Guinea, New Zealand; Cuba, Jamaica, Hispaniola (Haiti and Dominican Republic); mostly growing on rock, but not uncommon on rotten logs, tree trunks, and soil, in humid, mostly exposed habitats, usually above 1000 m.

United States of America North America| Mexico North America| Venezuela South America| Colombia South America| Ecuador South America| Peru South America| Brazil South America| Argentina South America| Africa| Madagascar Africa| India Asia| Asia| China Asia| Japan Asia| Mongolia Asia| South Korea Asia| North Korea Asia| Taiwan Asia| Indonesia Asia| New Zealand Cuba South America| Jamaica South America| Haiti South America| Dominican Republic South America|