Hagen's Distichium Moss

Distichium hagenii is a primarily high Arctic or high elevation species, morphologically close to D. inclinatum and sometimes considered as synonymous with that species. The primary difference is in the peristome. The 16 peristome teeth of D. hagenii are grouped in eight pairs united by a pale yellowish basal membrane, each tooth irregularly split and perforate. A report of the species from Newfoundland is referable to D. inclinatum (redetermined by G. R. Brassard according to H. A. Crum and L. E. Anderson 1981). In the southern part of the European range, it grows on sandy or loam soil close to the sea.

Plants minute to small, 0.5–1.0 cm high, yellowish green, not shiny, in dense tufts. Stems erect, often simple, rarely branched, radiculose at base. Leaves distichous, 2.5–3.0 mm long, abruptly narrowed from an oblong-ovate, sheathing base to a short, setaceous point, the acumina ½ to as long as the sheathing base; margins plane, crenulate above the shoulder; costa stout, shortly excurrent, ending in an awn; upper cells quadrate or irregularly hexagonal; basal cells short-rectangular, less than 25 µm long, moderately thick-walled. Autoicous or dioicous. Setae straight, 3–10 mm long, yellowish brown; capsules erect to suberect, oblong-ovoid to short-cylindric, symmetric to slightly asymmetric; opercula conic; annuli differentiated, in 2 rows of large cells, deciduous; peristome teeth 3–5 divided, reddish brown. Spores 30–60 µm in diameter, coarsely papillose.

Stems to ca. 2 cm, occasionally longer. Sexual condition paro-icous or synoicous. Seta to 2 cm, straight to somewhat flexuose, smooth, red or reddish brown, occasionally yellowish brown. Capsule brown, 1-1.5 mm, inclined, ovoid to oblong-ovoid, becoming ± wrinkled when dry; operculum to 0.3 mm; peristome teeth 16, united below by a pale yellow or hyaline membrane, the teeth in 8 groups of 2, irregularly split and perforated, smooth or very finely papillose. Spores finely papillose to roughened, 30-45 µm.

Distribution: China, Russia, Europe, and North America.

Habitat: on soil or rocks in alpine regions.

Swartzia hagenii (Ryan ex Philib.) Möll., Bot. Not. 1907: 142. 1907. Distichium inclinatum ssp. hagenii (Ryan ex Philib.) Amann, Fl. Mouss. Suisse 2: 87. 1919. Distichium inclinatum var. hagenii (Ryan ex Philib.) Mönk., Lanbm. Eur. 161. 1927. Distichium macrosporum C. Gao in X.-J. Li (ed.), Bryofl. Xizang. 17. 1985. Type. China: Xizang, Ji-long Co., G.-C. Zhang 801 (holotype IFSBH).

Distichium inclinatum subsp. hagenii (H. Philibert) J. J. Amann; D. inclinatum var. hagenii (H. Philibert) Mönkemeyer