Ceratodon Moss

Plants small to medium-sized, (5–)8–20(–30) mm high, dirty green or yellowish green, in dense tufts. Stems erect, simple or sparsely branched, radiculose at base. Leaves slightly appressed or contorted when dry, erect-patent when moist, lanceolate, 1.0–2.1 mm long, gradually acuminate; margins strongly reflexed or revolute, notched or irregularly serrulate near the apex; costa stout, percurrent to shortly excurrent; upper and median leaf cells quadrate, 7–10 µm wide, slightly thick-walled, smooth; basal leaf cells short-rectangular, 13–20 µm × 7–10 µm, rather thin-walled. Dioicous. Perichaetial leaves strongly convolute-sheathing at base, shortly acuminate at apex. Setae straight, 1.0–2.0 cm long, reddish brown; capsules cylindric, strongly inclined to horizontal, reddish brown, 2–3 times as long as wide, 1.0–2.0 mm × 0.5–0.7 mm, deeply furrowed when dry, somewhat strumose at base; opercula conic-rostrate; annuli differentiated, in 2–3 rows of thick-walled cells; peristome teeth lanceolate, divided nearly to the base, bordered with a hyaline band, finely papillose, basal membrane low. Spores 11–13 µm in diameter, yellowish, smooth or nearly so.

Plants in open to dense tufts, turfs, or mats, green, dark green, brownish green, light green or yellow-green, usually darker proximally, often tinged reddish brown or purple. Stems (0.2-)1-3(-4) cm. Leaves crowded, erect-patent to contorted or somewhat crisped, rarely straight when dry, lanceolate, ovate-lanceolate, or triangular-lanceolate, 0.35-2.8 mm, margins recurved to near apex or rarely plane, irregularly serrate to uneven or smooth distally, apices acute to short-acuminate or, rarely, obtuse; costa strong, sub-percurrent to excurrent, sometimes as a long, smooth awn, medial laminal cells (6.5-)8-12(-14) µm, cell walls even, usually of medium thickness, often somewhat thicker and rounded at the cell angles. Seta 1-3(-4) cm, various shades of red, orange, or yellow. Capsule oblong to long-cylindric, (1-)2-2.5(-3) mm, smooth to strongly sulcate when dry; free to united at their nodes, finely papillose to spinulose-papillose, dark red and bordered to completely pale and absent borders. Spores (10-)11-14(-17) µm.

Distribution: nearly worldwide.

Habitat: often on soil or on the base of rotten trees in open fields.

Didymodon purpureus (Hedw.) Hook. & Tayl., Musc. Brit. 65. 20. 1818. ? Ceratodon sinensis C. Müll., Nuovo Giorn. Bot. Ital., n.s. 3: 104. 1896. Type. China: Shaanxi (Schen-si), Giraldi s.n., July 1894 [holotype B, probably destroyed]. Ceratodon purpureus var. rotundifolius Berggr., Kongl. Svenska Vetensk. Acad. Handl. 13(7): 44. 1875.

Dicranum purpureum Hedwig, Sp. Musc. Frond., 136, plate 36. 1801; Ceratodon purpurascens (Hedwig) Jennings; C. purpureus var. purpurascens (Hedwig) Bridel; C. purpureus var. xanthopus Sullivant