Porotrichodendron superbum (Taylor) Broth.
-
Authority
Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
-
Family
Lembophyllaceae
-
Scientific Name
-
Description
Species Description - Plants relatively robust, not or obscurely stipitate-frondose, in pale- to yellow-green, extensive, interwoven mats. Primary stems (mostly small, rarely seen) creeping, secondary stems arising from upturning primary stem, the creeping stem continuing by innovations near the base of the stipe, the secondary stems at best obscurely stipitate, to 10 cm long, but mostly ca. 5-6 cm, the frond laxly pinnately branched, sometimes irregularly 2-pinnate, not complanate-foliate; in cross-section with 3-5 rows of small thick-walled cells surrounding abruptly larger thin-walled cells, central strand none or weakly differentiated; stipes (when differentiated) erect, usually not evident, <1 cm long, in cross-section with 6-8 rows of small thick-walled cells surrounding larger firm-walled cells, central strand of 1-2 rows of small firm-walled cells surrounding a few very thin-walled cells; paraphyllia absent; pseudoparaphyllia foliose to broadly foliose; axillary hairs with K-2) short brown basal cells and (1-)2-3 elongate hyaline distal cells. Primary creeping stem leaves reduced, widely spaced, appressed, oblong-ovate, 0.6-0.85 mm long, abruptly acuminate, decurrent; margins subentire to serrulate in the acumen, entire below, incurved at base of acumen, plane otherwise; costa none or very short and single; cells linear-fusiform, 10-15:1, smooth, thick-walled, porose; alar cells weakly differentiated, rectangular. Stipe leaves imbricate, appressed, oblong-ovate, 1.4-1.9 mm long, long-cuspidate, cordate to small-auriculate; margins subentire to serrulate above, entire below, plane or sometimes erect to incurved at base of cusp; costa single, ending ca. midleaf, sometimes forked, not projecting at apex; cells linear-fusiform, 15-25:1, smooth, thick-walled, the walls as wide or wider than the lumina, porose; alar cells subquadrate, thick-walled, porose, golden, in small groups, becoming thinner-walled and not porose or golden in the auricles. Secondary stem (continuation of stipe above branching) leaves not complánate, erect-spreading, broadly oblong to oblong-ovate, 1.4-1.7 mm long, obtuse-apiculate, deeply concave, cordate to small-auriculate; margins serrate above, subentire below, strongly incurved above, plane below; costa single, ending 2/3-3/4 the leaf length, becoming very slender above; cells fusiform, 48:1, smooth, firm-walled, not or somewhat porose, becoming shorter, ca. 2:1, and rhombic toward the apex; alar cells few, golden, subquadrate, filling the small auricle or not. Branch leaves erect-spreading, not complanate, ± turgid, ovate, oblong-ovate, or less often obovate, 0.9-1.3 mm long, obtuse-apiculate to short-acute, concave, cordate to small-auriculate; margins serrate above, subentire below, incurved above, rarely throughout, usually plane below; costa single, ending 1/2-2/3 the leaf length; cells fusiform, 4-8:1, smooth, firm- to thick-walled, ± porose, somewhat shorter in the apex; alar cells few but distinct, subquadrate, golden, filling the small auricle or not. Asexual propagula uncommon, of flagellate branches, arising at branch apices or branch leaf axils, <1 cm long, mostly simple; leaves appressed, ovate, 0.2-0.25 mm long, short-acuminate, ecostate. Dioicous. [Sporophytes not known from the West Indies; description from the Ecuadorian type.] Perichaetia large and conspicuous; leaves convolute, erect with ± spreading apices, oblong, 2.8-3.5 mm long. ± gradually acuminate; margins subentire, plane; costa none or short and obscure; cells linear, smooth, thick-walled, porose, becoming shorter and broader below. Setae long, somewhat roughened at extreme apex but otherwise smooth, reddish, ca. 1.5 cm long, ± flexuose when dry; capsules erect, cylindric, symmetric, ca. 3 mm long, with a well-developed, tapering neck; exothecial cells short-rectangular, ± firm-walled, not or scarcely smaller toward the mouth; annulus of 1-3 rows of oblong, firm-walled cells, deciduous; operculum long-rostrate, straight to slightly oblique, ca. 3 mm long; peristome pale, exostome teeth on the front surface ± cross-striolate below or with papillae arranged in horizontal rows, finely but densely papillose to papillose-spiculose above, scarcely trabeculate at back; endostome with a medium-high, smooth to papillose basal membrane, segments papillose to papillose-spiculose, keeled, perforate to gaping, somewhat shorter than the teeth, cilia none or rudimentary. Spores spherical, finely roughened, 12-17 µm diam. Calyptrae cucullate, naked, roughened at extreme apex.
-
Discussion
2. Porotrichodendron superbum (Taylor) Broth, ex Herzog, Biblioth. Bot. 87: 120. 1916; Leskea superba Taylor, London J. Bot. 5: 61. 1846; Hypnum superbum (Taylor) Müll. Hal., Syn. Muse. Frond. 2: 225. 1851; Porotrichum superbum (Taylor) Hampe, Flora 45: 456. 1862; Thamnium superbum (Taylor) Kindb., Hedwigia 41: 230. 1902. Plate 43, figures 8-15 Porotrichum crenulatum Midi. Hal., Hedwigia 37: 242. 1898,Wagner (1951: 192). Discussion. This distinctive species grows in a limited area in La Vega and Peravia provinces in central Dominican Republic. It is recognized by its sprawling habit, mostly 1-pinnate branching, and strongly concave leaves with a small-auriculate base. It differs from P. lindigii by its larger size, weakly developed stipe, and ovate branch leaves. Several species of Porotrichodendron have been described from Andean South America, and a few more from southeastern Brazil. I have not seen many of the types, but for the most part the differences seem trivial and many of the names may prove to be synonyms of P. superbum. Certainly Dominican material seems a good match for the Ecuadorian type of P. superbum.
-
Distribution
Range. Southern Mexico through Central America, Venezuela, Colombia, Ecuador, Peru, Bolivia; Hispaniola (Dominican Republic), reported from Haiti (Crum & Steere, 1958) but the specimen to which the record refers is from the Dominican Republic; growing on shrubs or tree bases, or on humus, in broadleaf cloud forests, at 1800-2600 m.
Mexico North America| Central America| Venezuela South America| Colombia South America| Ecuador South America| Peru South America| Bolivia South America| Dominican Republic South America|