Cyclodictyon roridum (Hampe) Kuntze

Authority

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

Family

Pilotrichaceae

Scientific Name

Cyclodictyon roridum (Hampe) Kuntze

Description

Species Description - Plants medium-sized to fairly robust, in dull to ± lustrous, whitish green to golden, sometimes red-tinged, mostly dense, small mats. Stems creeping, to ca. 5 cm long, irregularly but freely branched, complanate-foliate; in cross-section with a poorly differentiated hyalodermis over 1-3 rows of medium-sized firm-walled cells surrounding large thin-walled cells, central strand none; axillary hairs 2-celled, both hyaline, with a short basal one and an elongate apical one. Leaves ± contorted when dry, lateral leaves spreading to wide-spreading dry or moist, oblong-lanceolate to ovate-lanceolate, 1.5-2 mm long, ± asymmetric, gradually to ± abruptly slenderly long-acuminate, dorsal leaves erect to erect-spreading dry or moist, ovate-lanceolate to ovate, 1.3-1.7 mm long, symmetric, ± abruptly slenderly long-acuminate; margins bordered by 2-3 rows of narrow, elongate cells, confluent into a ca. 3-tiered apiculus of elongate cells, the apical one sometimes shorter, usually entire throughout (in the West Indies), sometimes serrulate above, plane or more often irregularly narrowly recurved; costa double, ending near the margins ca. the leaf length, scarcely tapering distally, sometimes projecting as a small spine; cells at midleaf relatively small, irregularly shaped, ± hexagonal to ellipsoidal, ± firm-walled, ca. 2-3:1, ca. 30 X 15 µm, usually > 15 between costal tips, often ca. 20, rarely <15 in scattered leaves, not differentiated in apex, becoming long-rectangular toward the insertion; alar cells not differentiated. Asexual propagula unknown. Autoicous. Perichaetia small, inconspicuous, along stems and primary branches; leaves pale, erect with spreading apices, small, lanceolate, 1.1-1.7 mm long, gradually long-acuminate; margins bordered by 2 rows of narrow, elongate cells, confluent into a very long, slender apiculus, entire, plane; costa usually absent; cells long-hexagonal to long-rectangular, thin-walled, becoming shorter toward the insertion. Setae elongate, smooth, reddish, 1.5-2.3 cm long, twisted, curved at extreme apex; capsules inclined to horizontal, short-cylindric, scarcely curved when dry, ± symmetric, ca. 2 mm long; exothecial cells subquadrate to short-rectangular, the vertical walls firm, the horizontal ones thin, obscurely collen-chymatous; annulus none; operculum long-rostrate from a conic base; exostome teeth reddish, bordered, on the front surface with a broad median furrow, the furrow pale with a zig-zag median line, the plates cross-striolate below, coarsely papillose above, trabeculate at back; endostome yellowish, with a relatively high, ± smooth basal membrane, segments fairly broad, papillose, keeled, narrowly perforate above, with baffle-like crosswalls, ca. as long as the teeth, cilia none or rarely single and rudimentary. Spores spherical, finely roughened, 8.5-12 µm diam. Calyptrae mitrate, constricted and lobed at base, naked, smooth.

Discussion

5. Cyclodictyon roridum (Hampe) Kuntze, Revis. Gen. Pl. 2: 835. 1891; Hookeria rorida Hampe, Linnaea 32: 155. 1863. Hookeria capillata Mitt., J. Linn. Soc., Bot. 12: 341. 1869; Cyclodictyon capillatum (Mitt.) Kuntze, Revis. Gen. Pl. 2: 835. 1891. Hookeria obliquicuspis Müll. Hal., Bull. Herb. Boissier 5: 564. 1897; Cyclodictyon obliquicuspis (Miill. Hal.) H. A. Crum & E. B. Bartram, Bull. Inst. Jamaica, Sci. Ser. 8: 50. 1958. Discussion. Cyclodictyon roridum is easily recognized by its relatively small laminal cells and long, slenderly acuminate leaf apex. The species is common in appropriate habitats at higher elevations in central Dominican Republic. Crum and Bartram (1958: 50) argued for the separation of C. obliquicuspis from C. capillatum on the basis of plant color, areolation, and sexuality. The type of C. obliquicuspis is indeed red-tinged. However, now that a good series of specimens is available, it seems as if the red coloration is ecologically induced and only in a minority of collections. The leaf apex in West Indian material is usually entire or almost so. In the Andes, though, plants are often encountered with distinctly serrulate margins. Initially this seemed a valid character, but even Mitten (1869), in describing C. capillatum, noted that some of the syntypes have entire margins and others have serrulate margins. Laminal cell size differences are minimal. In the Antilles the cells average about 34 µm long, whereas in the Andes the cells average about 40 µm long. These differences may be significant if, indeed, the Andean material were dioicous and the West Indian material autoicous, as given by Crum and Bartram. However, both are autoicous. The use of the name roridum has usually been misapplied, mostly to Lepidopilum tortifolium. However, the type (from Colombia) is unmistakably the taxon at hand.

Distribution

Range. Colombia, Ecuador, Peru; Jamaica, Hispaniola (Haiti and Dominican Republic); growing on moist humus, usually in humid forests, usually at elevations above 1500 m. Welch’s (1971: 95) report of this species from Florida is surely in error.

Colombia South America| Ecuador South America| Dominican Republic South America| Haiti South America| Jamaica South America| Peru South America|