Cyclodictyon bicolor (Schimp. ex Besch.) 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 bicolor (Schimp. ex Besch.) Kuntze

  • Description

    Species Description - Plants medium-sized, in ± lustrous, often soft and flaccid, whitish green to yellow-green, thin, sometimes extensive mats. Stems creeping, to ca. 5 cm long, irregularly to pinnately branched, often laxly foliate, complanate-foliate; in cross-section with a unistratose hyalodermis over 1-2 rows of medium-sized firm-walled cells surrounding larger thin-walled cells, central strand none; axillary hairs 2-celled, both hyaline, with a short basal one and an elongate apical one. Leaves often contorted when dry, lateral leaves spreading to wide-spreading moist or dry, oblong to broadly oblong-lanceolate, (0.7-)1-1.7 mm long, ± gradually to abruptly acute to short-acuminate, obscurely asymmetric, dorsal leaves erect to erect-spreading, broadly oblong to oblong-ovate, 0.85-1.6 mm long, ± symmetric; margins bordered by 1-2 rows of narrow, elongate cells, becoming shorter above and confluent into a several-celled, 2-3-tiered apiculus, the apical cell 4(-7):1, mostly strongly and usually bluntly serrate, rarely with sharp teeth but then the subapical ones usually blunt, plane; costa double, strong, ending 2/3-4/5 the leaf length near the margin, not tapering distally, sometimes expanded at apex into a small knob, usually projecting, occasionally the subapical cells also projecting; cells ± hexagonal to irregularly subisodiametric, thin-walled, 1-2:1, (20-)28-71 X 22-31 µm, usually <15 between costal tips, often 8-12, but sometimes 16-18, not differentiated in the apex, becoming longer and long-hexagonal to long-rectangular toward insertion; alar cells not differentiated. Asexual propagula unknown. Dioicous (or autoicous?). Perichaetia small, inconspicuous, on stems; leaves pale, erect, lanceolate-triangular, 0.85-1.4 mm long, ± gradually long-acuminate; margins bordered by 1-2 rows of narrow, elongate cells, confluent into filiform apiculus, subentire to bluntly serrate, plane; costa double or sometimes absent, ending near midleaf, the forks ± parallel; cells long-hexagonal, 3-4:1, thin-walled, scarcely differentiated toward insertion. Setae elongate, smooth, reddish, 1-1.8 cm long, curved at extreme apex; capsules inclined to horizontal, short-cylindric, curved, asymmetric, ca. 1.5 mm long; exothecial cells quadrate to short-rectangular, the vertical walls firm, the horizontal ones thin, obscurely collenchymatous; annulus none; operculum long-rostrate from a high-conic base, the rostrum pale; 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, almost smooth basal membrane, segments finely and sparsely papillose, keeled, narrowly perforate above, with baffle-like crosswalls, sometimes rudimentary, almost as long as the teeth, cilia none. Spores spherical, finely papillose, 11-14 µm diam. Calyptrae mitrate, constricted and lobed at base, naked, smooth.

  • Discussion

    2. Cyclodictyon bicolor (Besch.) Kuntze, Revis. Gen. Pl. 2: 835. 1891; Hookeria bicolor Schimp. Besch., Ann. Sci. Nat. Bot. VI, 3: 232. 1876. Plate 9, figures 4-8 Hookeria prasiophylla Besch., J. Bot. (Morot) 8; 177. 1894; Cyclodictyon prasiophyllum (Besch.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 935. 1907. Hookeria ulophylla Besch., J. Bot. (Morot) 8: 177. 1894; Cyclodictyon ulophyllum (Besch.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 936. 1907. Hookeria densifolia Broth, in Urb., Symb. Antill. 3. 428. 1903; Cyclodictyon densifolium (Broth.) Broth. in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 936. 1907. Hookeria limbatula Broth, in Urb., Symb. Antill. 3. 428. 1903; Cyclodictyon limbatulum (Broth.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 936. 1907. Hookeria antillarum Broth, in Urb., Symb. Antill. 3: 429. 1903, hom. illeg., non Mitt., J. Linn. Soc., Bot. 12- 343. 1869; Cyclodictyon dussii Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 935. 1907. Discussion. Cyclodictyon bicolor is distinguished by its more or less oblong leaves with a strong, projecting costa and a margin with irregularly spaced, blunt teeth. The border is 1-2 cells wide and an acute to short-acuminate apex is formed of relatively short cells. Because the border is occasionally only a single cell wide, C. bicolor might be confused with C. varians. However, it differs from that species in its leaves with a larger, multicellular apex and stronger costa. The real confusion is with C. albicaule. It is possible that C. bicolor and C. albicaule are only ecological forms of the same species. However, as there seem to be at least three good, apparently independent characters separating them, I have chosen to maintain two species. Cyclodictyon albicaule differs from C. bicolor in the ovate, strongly asymmetric lateral leaves, a weak, nonprojecting costa, and a border that is usually a single cell wide and subentire. Cyclodictyon bicolor is the most common species in the Lesser Antilles, as is suggested by the large number of synonyms, all described from Guadeloupe or Martinique. It has a scattered occurrence in the Greater Antilles.

  • Distribution

    Range. Trinidad; Cuba, Jamaica, Hispaniola (Dominican Republic), Puerto Rico, St. Kitts, Guadeloupe, Martinique, St. Vincent; usually growing on rotten wood or humus, in humid forests, at moderate elevations, usually below 1000 m.

    Cuba South America| Jamaica South America| Dominican Republic South America| Guadeloupe South America| Trinidad and Tobago South America| Puerto Rico South America| Saint Kitts and Nevis South America| Martinique South America| Saint Vincent and the Grenadines South America|