Ditrichum gracile

(Mitten) Kuntze

Revis. Gen. Pl. 2: 835. 1891,.

Basionym: Leptotrichum gracile Mitten Hooker’s J. Bot. Kew Gard. Misc. 3: 353. 1851
Synonyms: Leptotrichum crispatissimum Müller Hal. Ditrichum crispatissimum (Müller Hal.) Paris Ditrichum giganteum R. S. Williams
Treatment appears in FNA Volume 27. Treatment on page 453. Mentioned on page 450.

Plants in tufts, yellowish-brown to dark green, often shiny. Stems very variable in length, to 7 cm or more, simple or with relatively few branches; loosely compacted and then sparsely tomentose, or closely compact and rather densely tomentose. Leaves often ± falcate, slightly or not flexuose, subula of leaves often spirally twisted together, 4–7 mm, tapering ± gradually from an elongate ovate sheathing base to a long subula, lamina 1-stratose proximally, often 2-stratose distally in the subula; margins spinulose-denticulate in distal part of the subula or sometimes ± entire, often 2-stratose distally; costa occupying 1/4–1/3 width of leaf base, weakly abaxially convex, with poorly developed stereid bands abaxially and adaxially; cells of the subula and distal part of leaf base short, isodiametric to rhomboid to short rectangular, those of the leaf base becoming elongate, rectangular, with ± nodulose longitudinal walls, particularly near the costa, cells of the basal margins narrower. Specialized asexual reproduction unknown. Sexual condition dioicous; sporophytes rare; male plants slightly smaller than rarer female plants. Seta dark reddish-brown, to 2.5 cm, ± flexuose. Capsule erect and symmetric to slightly inclined, dark-brown, ± cylindric, 1.5–2 mm; operculum high-conic to conic-rostrate, to about 1 mm; peristome teeth about 400 µm, pale, 2-fid, divided to near base, densely papillose, fragile. Spores 12–15 µm, finely papillose.


Phenology: Capsules rarely produced, mature summer (Jul).
Habitat: Soil, rocks
Elevation: moderate to high elevations (0–4000 m)

Distribution

Greenland, B.C., Nfld. and Labr., N.W.T., Nunavut, Ont., Que., Alaska, Colo., Minn., Mont., Wyo., Mexico, Central America (Guatemala), Central America (El Salvador), South America (Colombia), Europe, Asia (Japan), Asia (Taiwan), Pacific Islands (New Guinea), Pacific Islands (New Zealand)

Discussion

B. H. Allen (1994) included Ditrichum crispatissimum and D. giganteum as synonyms of D. gracile, an interpretation we have followed here. As with D. flexicaule, a detailed molecular analysis of this and related taxa may help considerably in ascertaining taxonomic affinities.

Selected References

None.

Lower Taxa

None.
... more about "Ditrichum gracile"
forming a marginal border +  and not differentiated +
Rodney D. Seppelt +, Robert R. Ireland Jr. +  and Harold Robinson +
(Mitten) Kuntze +
ovate +  and elongate +
Leptotrichum gracile +
cucullate +
cleistocarpous +
inclined;erect +
cylindric +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
specialized +
dioicous +, sexual +  and asexual +
narrower +
excurrent;percurrent +
subpercurrent +
1/4 +  and 1/3 +
1/6 width of leaf base;1/3 width of leaf base +
shortrectangular +  and isodiametric +
rectangular;elongate;rectangular;isodiametric;rhomboid +
Greenland +, B.C. +, Nfld. and Labr. +, N.W.T. +, Nunavut +, Ont. +, Que. +, Alaska +, Colo. +, Minn. +, Mont. +, Wyo. +, Mexico +, Central America (Guatemala) +, Central America (El Salvador) +, South America (Colombia) +, Europe +, Asia (Japan) +, Asia (Taiwan) +, Pacific Islands (New Guinea) +  and Pacific Islands (New Zealand) +
moderate to high elevations (0–4000 m) +
Soil, rocks +
2-stratose +  and 1-stratose +
papillose +  and smooth +
dioicous +, monoicous +  and sexual +
flexuose +
falcate +
spinulose-denticulate +
high-conic +  and conic-rostrate +
with a longer , broader sheathing base +  and differentiated +
on short branches +  and axillary +
divided +  and 2-fid +
Capsules rarely produced, mature summer (Jul). +
filamentous +
Revis. Gen. Pl. +
dark reddish-brown +
flexuose +
elongate +
0 cm0 mm <br />0 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
papillose +
globose +
with relatively few branches +  and simple +
reaching 2 cm +  and short +
variable +
0 cm0 mm <br />0 m <br /> (7 cm70 mm <br />0.07 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Leptotrichum crispatissimum +, Ditrichum crispatissimum +  and Ditrichum giganteum +
Ditrichum gracile +
Ditrichum +
species +
specialized +
synoicous +, paroicous +, autoicous +, dioicous +  and sexual +
nodulose +
yellowish-brown +  and dark green +
slightly smaller +