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BFNA | Family List | BFNA Vol. 1 | Ditrichaceae

Ditrichum Hampe, Flora. 50: 181. 1867. Fl. Megapol. 216. 1788.
[conserved name, not Timm]

Greek di, two, and trichos, hair-like; the peristome is split longitudinally into two segments

Rodney D. Seppelt, Robert R. Ireland and Harold Robinson

Plants small to moderately robust, in loose to dense tufts, green to yellowish green distally, yellow-brown to brown proximally. Stems erect, short or reaching 2 cm or more, simple or sometimes with a few branches; rhizoids smooth, at base of stems. Leaves erect-spreading, rigid to flexuose or sometimes somewhat falcate, small to elongate, lanceolate to subulate from a more or less sheathing base; margins entire throughout or denticulate near the apex; costa single, 1/6--1/3 width of leaf base, percurrent or excurrent, occupying most of subula, with a single row of guide cells, and both adaxial and abaxial bands, or adaxial stereid band sometimes weak or rarely absent or; distal lamina cells quadrate to short-rectangular, becoming longer and thinner walled proximally toward margins, smooth or rarely papillose at both ends. Specialized asexual reproduction by rhizoidal tubers in some species. Sexual condition monoicous or dioicous; perichaetial leaves usually with a longer and more or less sheathing base and shorter subulate than stem leaves. Seta solitary, pale yellow to dark reddish brown, slender, long-exserted, erect or flexuose. Capsule mostly erect and symmetric, ovoid to cylindric, sometimes arcuate or ± inclined, smooth; annulus present, mostly large, deciduous; operculum conic to short-rostrate; peristome single, the 16 teeth split into 2 filiform segments or sometimes irregularly perforate or split, with or without a short basal membrane, papillose to spiculose, straight or ± twisted when dry. Calyptra cucullate. Spores rounded, 6--25 µm, very finely papillose and appearing smooth, but minutely to coarsely verrucose, or with somewhat vermicular ornamentation, yellow to brown.

Species ca. 90 worldwide (11 in flora). Known from all continents, including the maritime Antarctic region; occurring from near sea level to montane regions, on a wide range of soils, occasionally on rock; some species calciphilic.


Allen, B. 1994. Moss Flora of Central America. Part 1. Sphagnaceae-Calymperaceae. Missouri Botanical Garden. Britton, E. G. 1913. Ditrichaceae. North American Flora 15(1): 55--67. New York. Crum, H. A. and L. E. Anderson. 1981. Mosses of Eastern North America. Vol.1. New York. Grout, A. J. 1936. Moss Flora of North America north of Mexico. Vol. 1, Part 1. Newfane. Ireland, R. R. 1982. Moss Flora of the Maritime Provinces, Publications in Botany 13, National Museums of Canada. Ottawa. Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Nichinan. Nyholm, E. 1986. Illustrated Flora of Nordic Mosses. Fasc. 1. Fissidentaceae-Seligeriaceae. Stockholm.


Anderson, L. E. & V. S. Bryan. 1958. Systematics of the autoicous species of Ditrichum subg. Ditrichum. Brittonia 10: 121--137.
Best, G. N. 1893. Two new American mosses. Bull. Torrey Bot. Club 20: 116--117.
Bowers, F. D. & S. K.Freckmann. 1979. Atlas of Wisconsin bryophytes. Rep. Fauna Flora Wisconsin 16. 135 pp.
Corley, M. F. V., A. C. Crundwell, R. Düll, M. O. Hill, & A. J. E. Smith. 1981. Mosses of Europe and the Azores; an annotated list of species with synonyms from recent literature. J. Bryol. 11: 609--689.
Deguchi, H. & T. Matsui. 1986. Rhizoidal tubers of Ditrichum heteromallum in Japanese population. Proc. Bryol. Soc. Japan 4: 87.
Frisvoll, A. A. 1985. Lectotypifications including nomenclatural and taxonomic notes on Ditrichum flexicaule sensu lato. Bryologist 88: 31--40.
Grout, A. J. 1927. Studies in Ditrichum. Bryologist 30: 4--5.
Ireland, R. R. & H. Robinson. 2001. Taxonomic status of Ditrichum ambiguum and D. tortuloides. J. Hattori Bot. Lab. 91: 277--287.
Leiberg, J. B. 1893. Two new species of mosses from Idaho. Bull. Torrey Bot. Club 20: 112--116.
Matsui, T., H. Deguchi & R. D. Seppelt. 1985. Ditrichum lineare (Sw.) Lindb., with tubers in Asia. J. Jap. Bot. 60(2): 33--39.
Matsui, T. & Z. Iwatsuki. 1990. A taxonomic revision of the family Ditrichaceae (Musci) of Japan, Korea and Taiwan. J. Hattori Bot. Lab. 68: 317--366.
Novotny, I. 1996 (1997). Variability and distribution of Ditrichum flexicaule sensu lato in the Czech and Slovak Republics. Acta Mus. Moraviae, Sci. Nat. 81: 157--192.
Risse, S. 1985. Rhizoidal tubers on Ditrichum heteromallum (Hedw.) Britt. J. Bryol. 13: 527--531.
Robinson, H. 1966. New or little known mosses from the eastern United States. Bryologist 69: 105--109.
Seppelt, R. D. 1982. A monographic revision of the genus Ditrichum (Musci: Ditrichaceae). I. Australian and New Zealand species. J. Hattori Bot. Lab. 51: 99--150.

1 Plants loosely to densely tufted or gregarious; stems, if tomentose, only so at the extreme base.   (2)
+ Plants densely tufted, stems ± tomentose proximally.   (3)
2 (1) Stems 1--4 cm; leaves to 3 mm, from an ovate-sheathing base sharply contracted to the subula; costa abaxially strongly convex; lamina cells near costa with weakly nodulose longitudinal walls; plants commonly fruiting.   Ditrichum flexicaule
+ Stems to 7 cm or more; leaves from an elongate-ovate base tapering gradually to the long slender subula; costa abaxially weakly convex; basal laminal cells with weakly to strongly nodulose longitudinal walls; rarely found fruiting.   Ditrichum gracile
3 (1) In cross section, distal leaf lamina partially 1-stratose with 2-stratose margins.   (4)
+ In cross section, distal leaf lamina 2-stratose from costa to margins.   (8)
4 (3) Leaves erect-appressed to erect-patent when moist.   (5)
+ Leaves erect-spreading when moist.   (6)
5 (4) Leaves oblong-lanceolate, widest proximally middle, tapering to a blunt apex; lamina cells thin walled, rectangular throughout, slightly shorter and narrower towards apex; seta to 2.5 cm, yellowish to orange-brown, erect; peristome teeth 200--220 µm, perforate, divided into 2 adhering filaments, finely papillose.   Ditrichum lineare
+ Leaves lanceolate to linear-lanceolate, gradually acuminate; lamina cells ± incrassate, subquadrate to short-rectangular distally, elongate-rectangular proximally; seta to 1.5 cm, reddish with age; peristome teeth 200--250 µm, the filaments finely and obliquely ridged and lightly papillose.   Ditrichum pusillum
6 (4) Stems fastigiately branched from base, dichotomous distally; leaves linear-lanceolate, margins subserrulate distally, apex coarsely toothed; seta to 2.5 cm, pale yellow, capsule straight and erect or slightly curved, orange- to dark red-brown at maturity, elliptical, narrowed at mouth, 2--3 mm, flattened when dry; peristome teeth 600--800 µm, spiculose-papillose; autoicous.   Ditrichum montanum
+ Stem branching from distally base; leaves lanceolate to linear-lanceolate, margins entire to serrulate distally, apex weakly toothed; seta shorter, 0.8--2 cm, red to orange-brown; capsule symmetric to slightly curved, 1--3 mm, not flattened when dry; peristome teeth 200--500 µm, papillose to spiculose; dioicous.   (7)
7 (6) Stems to 2 cm, often branched; leaves 1.5--4.5 mm, apex entire or serrulate, margins broadly recurved from base to leaf middle; leaf cross section 2-stratose on margins and sometimes near costa; seta 1.5--2 cm, red; capsule usually symmetric, straight and erect, rarely curved, 1.5--3 mm long, dark brown to reddish; peristome teeth 200--500 µm, twisted when dry.   Ditrichum ambiguum
+ Stems to 0.5 cm, seldom branched; leaves 1--3 mm, apex serrulate, margins plane or narrowly recurved from distally leaf base to leaf middle; leaf cross section 2-stratose only at or near margins; seta 0.8--1.2 cm, orange-yellow, brownish or reddish; capsule usually asymmetric, erect, curved, 1--2 mm, yellow or light brown; peristome teeth 200 µm, nearly straight.   Ditrichum tortuloides
8 (3) Stem leaves 1.5--3 mm, from an ovate to oblong base gradually tapered to a channelled subula, erect-patent to subsecund.   Ditrichum heteromallum
+ Stem leaves longer, 3--7 mm, long-subulate from an ovate to short- rectangular base, spreading, flexuose to subsecund; autoicous.   (9)
9 (8) Leaves to 5 mm; seta to 2.5 cm, orange-yellow, becoming reddened at maturity; capsule ovoid-cylindric, ± asymmetric and slightly curved, pale brown, suberect, flattened when dry; peristome teeth to 1500 µm, densely spiculose-papillose; spores yellow-brown, 11--19 µm, vermicular papillose-verrucose.   Ditrichum rhynchostegium
+ Leaves 3--7 mm; seta 1--3 cm, yellow or becoming reddish-brown at the base when mature; capsules subcylindric to cylindric, not flattened when dry; peristome teeth to 800 µm, finely papillose to spiculose-papillose; spores brown, 15--30 µm, coarsely roughened-papillose.   (10)
10 (9) Leaves narrow filiform-subulate from an ovate-lanceolate sheathing base; seta 1--3 cm, yellow; capsule cylindric, 1.5--3 mm; peristome teeth pale yellow-brown, to 300 µm, irregularly perforate, finely papillose; spores 20--30 µm.   Ditrichum schimperi
+ Leaves long-subulate from a short-ovoid sheathing base; seta to 2.5 cm, yellow, becoming reddened at the base with maturity; capsule suberect, subcylindric, 1--2.5 mm; peristome teeth pale brown to orange-brown, 300--800 µm, spiculose-papillose; spores 15--30 µm.   Ditrichum pallidum

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