Leptodictyum

(Schimper) Warnstorf

Krypt.-Fl. Brandenburg 2: 867. 1906.

Etymology: Greek leptos, thin, alluding to fine outline of laminal cells
Basionym: Amblystegium subg. Leptodictyum Schimper Syn. Musc. Eur., 595. 1860
Treatment appears in FNA Volume 28. Treatment on page 289. Mentioned on page 266, 290, 291, 304, 305, 655, 657.
 TaxonIllustrator 
AmblLeptodictyumRiparium.jpegLeptodictyum ripariumPatricia M. Eckel

Plants medium-sized, green, yellow-green, or brown-green. Stems irregularly to sparingly branched; hyalodermis absent, central strand weakly developed; paraphyllia absent; rhizoids or rhizoid initials on stem or abaxial costa insertion, rarely forming tomentum, slightly branched, smooth; axillary hairs well developed and many, or small, delicate, sparse, distal cells hyaline when young. Stem and branch leaves erect to widespreading, not secund, oblong-lanceolate, not plicate, 2–6 mm; base not decurrent; margins plane, entire or obscurely serrulate, limbidia absent; apex acuminate, acumen plane; costa single, ending 3/5–3/4 leaf length; alar cells differentiated or not, rectangular, enlarged, walls thin, region gradually delimited, not extending up leaf; medial laminal cells linear, 42–117 µm; marginal cells 1-stratose. Sexual condition autoicous. Capsule inclined to horizontal, cylindric, curved; peristome perfect; exostome teeth bordered; endostome cilia 1–4, nodulose. Spores 10–19 µm.

Distribution

Nearly worldwide

Discussion

Species 7 (2 in the flora).

L. Hedenäs (2003b) included in Leptodictyum only a single, variable species, L. riparium, with L. humile treated in Amblystegium. According to A. Vanderpoorten et al. (2001, 2002b), L. humile should be treated as a member of Hygroamblystegium. From a morphological point of view, there is a continuum between Hygroamblystegium humile and H. tenax, the only actual feature distinguishing the two being the length of the costa, which continuously varies from ceasing at mid leaf to percurrent. The most recent molecular analyses (Vanderpoorten, pers. comm.) suggest that L. riparium falls within a completely unrelated clade together with large Campylium species. Vanderpoorten et al. (2002b) suggested that L. riparium appears more closely related to Campyliadelphus chrysophyllus and Campylium stellatum than to species of Amblystegium. In Leptodictyum, the endostome segments are hyaline and filiform; the spores are minutely papillose.

Selected References

None.

Key

1 Stems 6-20 cm, flaccid; basal laminal cell walls lax; alar regions differentiated. Leptodictyum riparium
1 Stems 3-6 cm, stiff; basal laminal cell walls firm; alar regions not differentiated. Leptodictyum wallacei

"narrower" is not a number.

... more about "Leptodictyum"
not +  and separating +
acuminate +
Steven G. Newmaster +
(Schimper) Warnstorf +
not decurrent +
Amblystegium subg. Leptodictyum +
erect +  and widespreading +
oblong-lanceolate +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
cucullate +
inclined +  and horizontal +
cylindric +
rectangular +
enlarged +
not +  and differentiated +
appendiculate +
Nearly worldwide +
Greek leptos, thin, alluding to fine outline of laminal cells +
brownish +  and yellowbrown +
short +  and narrow +
3/5 (?) +  and 3/4 (?) +
serrulate +  and entire +
autoicous +  and sexual +
multistratose +  and 1-stratose +
hexagonal +, rectangular +  and short-linear +
short-rostrate +, rostrate +  and conic +
obovate +, oblong +, ovate +  and lanceolate +
Krypt.-Fl. Brandenburg +
not secund +  and branched +
erect +  and widespreading +
oblong-lanceolate +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Leptodictyum +
Amblystegiaceae +
incrassate +
brown-green +, yellow-green +  and green +
transitional +