Porotrichum mutabile Hampe
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Authority
Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
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Family
Neckeraceae
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Scientific Name
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Description
Species Description - Plants medium-sized to robust, to ca. 10(-15) cm tall, stipitate-frondose, in mostly pale- to yellow-green to golden, wiry colonies. Primary stems creeping, not strikingly different from stipe, secondary stems mostly arising from upturning primary stem, the creeping stem continuing by innovations near the base of the stipe, the secondary stems distinctly stipitate, 1-2 cm tall, mostly erect, frondose, irregularly and weakly 2-pinnate, usually compla-nate-foliate; in cross-section with (3-)6-8(-10) rows of small thick-walled cells, with 8-12 rows in stipe, surrounding large thin-walled cells, in stipe the internal cells abruptly larger and thick-walled, grading to thin- to firm-walled cells internally, central strand well differentiated; paraphyllia absent; pseudoparaphyllia broadly foliose; axillary hairs with a single rectangular to 2 short-rectangular to subquadrate basal cells and 2-3 elongate distal cells, all cells brownish. Primary creeping stem leaves reduced, widely spaced, erect-spreading to spreading, lanceolate-triangular, (0.8-) 1.2-1.5(-1.7) mm long, gradually long-acuminate; margins subentire throughout or serrulate above, plane or irregularly incurved above; costa single, ending 1/3-1/2 the leaf length; cells linear-fusiform, smooth, firm-walled, porose, becoming shorter toward the insertion; alar cells weakly differentiated with only 23 subquadrate cells in extreme basal angles. Stipe leaves often imbricate, spreading from a ± erect base, not complanate, lanceolate- to ovate-triangular, 1.5-2 mm long, slenderly long-acuminate, ± concave; margins subentire throughout or serrulate in the extreme apex, erect to incurved above; costa single, weak, ending at or below midleaf; cells linear-fusiform, (8-) 10-25:1, smooth, firm-to thick-walled, porose, becoming shorter, thicker-walled and more porose toward the insertion; alar cells not or weakly differentiated. Secondary stem (continuation of stipe above branching) leaves complánate, spreading, oblong-ovate, 3-5 mm long, abruptly short-acuminate, ± concave at base, sometimes obscurely plicate when dry; margins sparsely serrate at apex with multicellular teeth, subserrulate to subentire below, plane; costa single, ending 2/3-3/4 the leaf length, smooth; cells fusiform, 8-10:1, smooth, mostly firm-walled, somewhat to strongly porose, becoming shorter and ± rhombic, 2-4: 1 above, becoming thicker-walled and more strongly porose toward the insertion; alar cells few, subquadrate to short-rectangular, in 1-2 rows, extending up the margins by 3-5 cells. Branch leaves spreading to wide-spreading, complanate, oblong-ligulate with a somewhat expanded base, 1.7-2.5 mm long, abruptly short-acuminate to cuspidate, slightly to strongly concave; margins serrate at apex with the teeth 1(-3)-celled, serrulate to subentire below, plane to irregularly incurved; costa single, ending 1/2-3/4 the leaf length, not or scarcely projecting at apex; cells fusiform, 8-10:1, smooth, firm- to thick-walled, porose, becoming shorter and ± rhombic above, becoming shorter and thicker-walled across the insertion; alar cells few in extreme angles, short-rectangular, thinner-walled than other cells at insertion. Asexual propagula common, of flagellate branches arising from branch apices or axils of branch leaves, simple or branched, few to numerous, rarely absent; leaves laxly disposed, lanceolate, 0.2-0.3 mm long, with subentire margins, ecostate, with fusiform, smooth cells. Dioicous. Perichaetia along primary branches; leaves spreading from a convolute base, broadly oblong-lanceolate, 1.8-2.4 mm long, abruptly long-acuminate; margins subserrulate in the acumen, subentire below, plane; costa none or single and very short; cells linear, smooth, thick-walled, porose, becoming shorter toward the insertion. Setae short, smooth, reddish, 4-5 mm long; capsules erect, broadly cylindric, symmetric, ca. 2 mm long; exothecial cells subquadrate to short-rectangular, firm-walled, becoming somewhat smaller in 2-3 rows at the mouth; annulus of 2-3 rows of oblong firm- to thick-walled cells; operculum obliquely rostrate from a conic base, ca. 1.5 mm long; exostome teeth on the front surface cross-striolate with densely overlying papillae only on basalmost 4-8 pairs of plates, densely papillose above, scarcely trabeculate at back; endostome with a medium-high, smooth basal membrane, segments finely and densely papillose, keeled, broadly perforate to gaping, ca. as long as the teeth, cilia rudimentary to absent. Spores spherical, finely roughened but appearing almost smooth, 11-15 µm diam. Calyptrae cucullate, naked, smooth.
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Discussion
2. Porotrichum mutabile Hampe, Flora 45: 456. 1862, nom. nov. \ Neckera flabellcitci Hampe, Linnaea 31: 525, 1862, hom. illeg., non (Sm.) Mitt., J. Proc. Linn. Soc., Bot. Suppl. 1: 118. 1859 [= Homaliodendron flabella-tum (Sm.) M. Fleisch.]; Porotrichum variabile Hampe, Ann. Sci. Nat. Bot. V, 4: 375. 1865, nom. illeg.; Tham-nium variabile (Hampe) Kindb., Hedwigia 41: 233. 1902, nom. illeg. Plate 48, figures 1-9 Porotrichum insularum Mitt., J. Linn. Soc., Bot. 12: 462. 1869. Meteorium husnotii Schimp. ex Besch., Ann. Sci. Nat. Bot. VI, 3: 215. 1876, nom. nud. in syn. Porotrichum hansenii Müll. Hal., Hedwigia 37: 243. 1898; Thamnium hansenii (Müll. Hal.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 862. 1906. he West Indies and has most commonly been called P. insularum. It is characterized by spreading stipe leaves and oblong-ligulate branch leaves that are toothed only toward the apex. The mature branch leaves are mostly about 4:1 (rarely only 3-3.5:1) and have an abruptly short-acuminate apex. In our flora it is most similar to P. korthalsianum, but in that species the branch leaves are relatively shorter and have an obtuse apex. Allen (1994) synonymized P. mutabile with P. longirostre, but I cannot agree. In P. longirostre the leaves are differently shaped, strikingly narrower at the insertion and almost elliptic, relatively shorter (mostly about 2.5:1, compared with 4:1), with more strongly toothed margins. Porotrichum mutabile (or the homotypic P. variabile) is well named. It is extremely variable. However, the variation seems to be altitudinally correlated. At low elevations, in relatively exposed habitats, branches are fewer and shorter with the branch leaves densely disposed and overlapping, ± flat, and somewhat broader. At high elevations, in sheltered cloud forests, the branches are more numerous and elongate, with laxly disposed, widely spaced, concave, narrow leaves.
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Distribution
Range. Nicaragua to Panama, Colombia, Venezuela, Ecuador, Trinidad; Cuba, Jamaica, Hispaniola (Haiti and Dominican Republic), Puerto Rico, Saba, St. Kitts, Montserrat, Guadeloupe, Dominica, Martinique, St. Vincent, Grenada; growing on tree trunks, branches, and roots, less often rocks, in humid to cloud forests, at 400-1900 m.
Nicaragua Central America| Costa Rica South America| Panama Central America| Colombia South America| Venezuela South America| Ecuador South America| Trinidad and Tobago South America| Cuba South America| Jamaica South America| Haiti South America| Dominican Republic South America| Puerto Rico South America| Saba South America| Saint Kitts and Nevis South America| Montserrat South America| Guadeloupe South America| Dominica South America| Martinique South America| Saint Vincent and the Grenadines South America| Grenada South America|