Ditrichum heteromallum

(Hedwig) E. Britton in N. L. Britton et al.

in N. L. Britton et al., N. Amer. Fl. 15: 64. 1913,.

Basionym: Weissia heteromalla Hedwig Sp. Musc. Frond., 71. 1801
Synonyms: Didymodon homomallus Hedwig Ditrichum homomallum (Hedwig) Hampe Ditrichum zonatum (Bridel) Kindberg Ditrichum zonatum var. scabrifolium Dixon
Treatment appears in FNA Volume 27. Treatment on page 453. Mentioned on page 451, 454, 455.

Plants in loose to dense tufts, yellowish green. Stems to 1 cm, simple, seldom branched. Leaves 1.5–3 mm, erect-spreading, sometimes slightly secund, from an ovate to oblong base tapering gradually to a long channelled subula, lamina 2-stratose distally; margins plane, 1-stratose proximally, 2-stratose in the middle to distal parts; costa broad, occupying most of the subula, in section with a distinct abaxial and poorly developed adaxial stereid band; cells of subula and distal lamina elongate-rectangular, longer in the leaf base, smooth or sometimes papillose at both ends, especially near leaf apices. Specialized asexual reproduction by rarely produced rhizoidal tubers. Sexual condition dioicous. Seta reddish-brown, 1–2.5 mm. Capsule erect, reddish-brown, oblong to cylindric, symmetric, 0.5–1.5 mm; peristome teeth pale orange, about 300 µm, lightly papillose; operculum conic-rostrate, blunt, 0.4–0.5 mm. Spores 10–15 µm, finely papillose.


Phenology: Capsules mature summer (Jun–Aug).
Habitat: Soil
Elevation: low to high elevations (50-1500 m or higher)

Distribution

B.C., Alaska, Oreg., Wash., South America (Colombia), Europe, Asia (China), Asia (Japan), Asia (Taiwan), Atlantic Islands (Iceland)

Discussion

Rhizoidal tubers were first reported for Ditrichum heteromallum by S. Risse (1985) from European material and have also been noted in Japanese material by H. Deguchi and T. Matsui (1986). They have the appearance of short filaments with swollen, contorted rhizoid cells. Ditrichum zonatum (Bridel) Kindberg, including the var. scabrifolium Dixon, appears to be only a small form of D. heteromallum with shorter, appressed leaves that are often more 2-stratose, especially near the base, and leaf cells that are sometimes papillose at the ends. We have not seen specimens that support the Wisconsin report by F. Bowers and S. Freckman (1979) and believe the record to be dubious.

Selected References

None.

Lower Taxa

None.
... more about "Ditrichum heteromallum"
forming a marginal border +  and not differentiated +
Rodney D. Seppelt +, Robert R. Ireland Jr. +  and Harold Robinson +
(Hedwig) E. Britton in N. L. Britton et al. +
tapering +, ovate +  and oblong +
Weissia heteromalla +
cucullate +
reddish-brown +
cleistocarpous +
oblong +  and cylindric +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
specialized +
papillose +
dioicous +  and sexual +
elongate-rectangular +
excurrent;percurrent +
subpercurrent +
1/6 width of leaf base;1/3 width of leaf base +
shortrectangular +  and isodiametric +
B.C. +, Alaska +, Oreg. +, Wash. +, South America (Colombia) +, Europe +, Asia (China) +, Asia (Japan) +, Asia (Taiwan) +  and Atlantic Islands (Iceland) +
low to high elevations (50-1500 m or higher) +
papillose +  and smooth +
dioicous +, monoicous +  and sexual +
flexuose +
lanceolate +  and subulate +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
2-stratose +  and 1-stratose +
blunt +  and conic-rostrate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
with a longer , broader sheathing base +  and differentiated +
on short branches +  and axillary +
Capsules mature summer (Jun–Aug). +
filamentous +
in N. L. Britton et al., N. Amer. Fl. +
reddish-brown +
flexuose +
elongate +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
papillose +
globose +
branched +  and simple +
reaching 2 cm +  and short +
0 cm0 mm <br />0 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Didymodon homomallus +, Ditrichum homomallum +, Ditrichum zonatum +  and Ditrichum zonatum var. scabrifolium +
Ditrichum heteromallum +
Ditrichum +
species +
specialized +
synoicous +, paroicous +, autoicous +, dioicous +  and sexual +
small +  and medium-sized +