Dicranodontium

Plants medium-sized to large, in loose to dense tufts, yellowish brown to dark green. Stems erect, simple or sparingly branched; rhizoids smooth, scattered along stems or present on branch bases. Leaves gradually or abruptly narrowed, tubulose to subtubulose proximally, weakly concave to subtubulose distally, lamina 1-stratose, acute, erect-flexuose to falcate-secund, occasionally somewhat spreading, sometimes somewhat auriculate at base; margins incurved, serrulate to nearly entire near apex; leaf apex setaceous; costa single, excurrent, broad, filling 1/5–1/2 of leaf base and most of subula, sometimes indistinct, rough distally on abaxial surface, rhizoids at base occasionally on adaxial and commonly on abaxial surfaces, with a median row of guide cells, two stereid bands, epidermal cells differentiated on both surfaces; cells incrassate nearly throughout, distal rectangular to linear, smooth or prorate on abaxial surface, becoming broader toward base, often pitted, alar cells thin-walled, inflated, hyaline or sometimes reddish. Specialized asexual reproduction by deciduous leaves. Sexual condition dioicous. Perigonial leaves broad at base, more abruptly narrowed to a shorter setaceous apex than stem leaves, paraphyses filamentous, antheridia few. Perichaetial leaves often with broader and longer bases more abruptly narrowed distally than stem leaves, paraphyses absent, archegonia few. Seta solitary, smooth, elongate, curved to cygneous, erect-sinuous when dry. Capsule erect and symmetric, oblong-cylindric, smooth; annulus and stomata absent; operculum long-rostrate; peristome single, teeth 16, inserted below mouth, divided nearly to base, vertically striolate nearly to tips. Calyptra cucullate, smooth, entire at base, naked. Spores spherical, smooth.

Distribution

North America, Mexico, Central America, South America, Europe, Asia, Africa, Australia.

Discussion

Species 7 (3 in the flora).

Dicranodontium can be confused with Campylopus but difffers primarily in two features: (1) the rhizoids, in addition to being on both surfaces of the costa in the two genera, are scattered along the stems or present at branch bases in Dicranodontium while they are only at the branch bases and branch primordia in Campylopus; and (2) Campylopus usually has ridges or low lamellae on the abaxial surface of the costa near the leaf middle while the costa in the mid-leaf region of Dicranodontium is smooth. Dicranodontium rarely produces perichaetia and perigonia so sporophytes are extremely rare in North America.

Selected References

Frahm, J.-P. 1997. A taxonomic revision of Dicranodontium (Musci). Ann. Bot. Fenn. 34: 179–204.

Ireland, R. R. 1989. The moss genus Dicranodontium (Dicranaceae) in Canada. Canad. J. Bot. 67: 640–649.

Lower Taxa

Dicranodontium asperulum, Dicranodontium denudatum, Dicranodontium uncinatum

Key

1	Leaf bases spreading from stem at ca. 45° or sometimes more when wet, sharply serrulate to serrate at shoulders.	Dicranodontium asperulum
1	Leaf bases appressed to spreading from stem at about 30° when wet, entire at shoulders	> 2
2	Leaves long, often 8 mm or more, not auriculate; costa distinct.	Dicranodontium uncinatum
2	Leaves short, seldom reaching 8 mm, auriculate; costa indistinct.	Dicranodontium denudatum