Campylopus Moss

Campylopus arctocarpus much resembles C. flexuosus, to which it seems closely related, but is distinguished mainly by the different transverse section of the costa with adaxial stereids. Other examples of the phenomenon of “sister species” differing only by the transverse section of the costa are found in the genus.

Plants 1-3 cm, in dark green tufts, evenly foliate, stems reddish tomentose. Leaves 6-8 mm, erect-patent when wet, crisped when dry, lanceolate, ending in a straight concolorous tip; alar cells inflated, hyaline or (in older leaves) reddish brown; basal laminal cells rectangular, thick-walled with pitted cell walls, ca. 3-6:1, narrower and thinner walled at margins, forming a small border; distal laminal cells subquadrate to oblique or rhombic, arranged in distinct rows; costa filling up to half of the leaf width, shortly excurrent in a dentate awn, in transverse section showing abaxial and adaxial stereid bands. Specialized asexual reproduction by micro-phyllous branches. Sporophytes absent in flora area.

Dicranum arctocarpum Hornschuch in C. F. P. von Martius et al., Fl. Bras. 1: 12. 1840

Campylopus arctocarpus (Hornsch.) Mitt. Jour. Linn
Soc. 12: 87. 1869.
Dicranum arctocarpum Hornsch. in Mart. Fl. Bras. I 2 : 12. 1840. Thysanomitrium scabrisetitm Hampe, Ic. Muse. pi. 23. B. 1844. Dicranum stenopus C. Miill. Syn. 1: 404. 1848.
Plants in rather compact green tufts; stems branching, up to 10 cm. high, radiculose to near theapex, rather equally foliose or with the leaves comose at intervals: leaves rather crowded, erect-spreading, somewhat curved or flexuous, often secund toward the apex of the stem, 6-8 mm. long, from an oblong-lanceolate base, gradually narrowed to a short, stout, denticulate point, the leaf -blade 3 or 4 cells wide a little below its termination and serrulate about one fourth down; costa shortly excurrent, ribbed and serrulate on the back above, about 175 m wide just above the base, in cross-section showing a median row of large cells with stereid-bands above and below, the lower band with one row of larger cells near the dorsal surface; alar cells more or less conspicuous, from red to hyaline, the cells next above mostly rhomboidal to rectangular with pitted walls except near the margin, higher up becoming shorter, oblong to rhomboidal, in distinct rows with not pitted walls; perichaetial leaves shorter than the stem-leaves, convolute about one half up and rather abruptly narrowed to a serrulate point: seta 7 mm. long, somewhat rough above, slightly curved when moist, nearly straight when dry: capsule oblong, 1.5 mm. long without the lid, not quite regular, furrowed when dry, rugulose at the base; peristome-teeth 50 p wide at the base; lid conic-rostrate, as long as the capsule: calyptra ciliate at the base : spores rough, 1 2 y. in diameter.
Type locality: Montevideo, Uruguay.
Distribution: Near Cinchona. Jamaica; also in South America.