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BFNA | Family List | BFNA Vol. 1 | Dicranaceae

Dicranella (J. K. A. Müller) Schimper, Coroll. Bryol. Eur. 13. 1856.
[A resemblance in miniature to the genus Dicranum]

Howard A. Crum

  • Anisothecium Mitten
  • Dicranella subg. Anisothecium (Mitten) Kindberg
  • Dicranella subg. Microdus (Bescherelle) Brotherus
  • Microdus Bescherelle

    Plants in loose to dense tufts, green to yellowish green, sometimes reddish. Stems 0.5--5(--11) cm, erect, simple or forked, rhizoids at bases of branches or stems. Leaves short- to long-lanceolate, concave to keeled, rarely flat, erect-spreading or- appressed to squarrose, straight or falcate-secund, occasionally curled or crispate when dry; apices acute to obtuse, tips not deciduous; margins plane to recurved, entire, serrulate or serrate distally, entire proximally; laminae 1-stratose or rarely 2-stratose on margins; costa single, subpercurrent to excurrent, smooth or papillose to serrulate on abaxial surface, guide cells various, two stereid bands above and below, sometimes slightly differentiated or lacking, adaxial and abaxial epidermal layers of cells differentiated or undifferentiated; laminal cell walls weakly bulging, or bulges lacking; leaf cells nonpitted, smooth, walls sometimes irregular; distal and median laminal cells long, rectangular to linear, proximal cells rectangular to linear, alar cells not differentiated. Specialized asexual reproduction lacking or tubers borne on rhizoids. Sexual condition dioicous; male plants as large as female plants; perigonial leaves ovate, concave, short-acuminate; perichaetial leaves weakly sheathing; sometimes reported to be autoicous. Seta solitary, smooth, elongate, erect or flexuose, twisted when dry, yellow or red, brown with age. Capsule erect or inclined, usually ovoid, oblong or cylindric, sometimes subglobose, straight or arcuate, smooth, struma present or absent, plicate or furrowed when dry, often contracted below the mouth, sometimes obliquely so, annulus of 1--2 rows of deciduous or persistent cells; operculum long-rostrate to conic, often arcuate; peristome single, 16 teeth, split ca. 1/2 their length into 2 divisions, vertically pitted-striolate below, papillose above, red. Spores 10--25 μm, spheric, smooth to minutely papillose. Calyptra cucullate, smooth, covering ca. 1/2 of capsule, fugacious.

    Species ca. 215 (11 in the flora): widespread.

    These plants resemble those of Dicranum but are smaller and have scarcely differentiated alar cells. As presented here, the genus includes the subgenera Dicranella and Microdus, which can be differentiated only on the basis of a few sporophytic characters and therefore are best regarded as subgenera: subg. Microdus has a yellowish seta, an annulus, and short, papillose peristome teeth that are entire or bluntly and shortly 2-fid; subg. Dicranella has a red or yellow seta, an annulus (in most cases), and vertically pitted-striolate peristome teeth rising from a short basal membrane. The genus Anisothecium, differing from Dicranella only in having no annulus and longer peristome teeth rising from a somewhat higher membrane, is included here in subg. Dicranella. What are here considered to be trivial differences separating the subgenera Dicranella and Microdus are very likely attributable to evolutionary reduction. The synonymies have been taken largely from R. S. Williams (1913).

    SELECTED REFERENCES

    Allen, B. 1994. Moss Flora of Central America. Part 1, pp. 92--101. Brotherus, V. F. 1924. Musci. In: A. Engler, Die natürlichen Pflanzenfamilien. Ed. 2. Vol. 10, pp. 177--178, 181--182. Leipzig. Crum, H. and L. E. Anderson. 1981. Mosses of Eastern North America. Vol. 1, pp. 165--176. New York. Lawton, E. 1971. Moss Flora of the Pacific Northwest. Pp. 66--70. Nichinan. Williams, R. S. 1913. Bryales: Dicranaceae. North American Flora 15(2): 77--158. New York Botanical Garden, Bronx, N.Y.

    OTHER REFERENCES

    Bowers, F. D. and S. K. Freckmann. 1979. Atlas of Wisconsin bryophytes. Rep. Fauna Fl. Wisconsin 16. 135 pp.
    Crundwell, A. C. and E. Nyholm. 1977. Dicranella howei Ren. & Card. and its relationship to D. varia (Hedw.) Schimp. Lindbergia 4(1--2): 35--38.
    Flowers, S. 1973. Mosses: Utah and the West. Provo, Utah.
    Grout, A.J. 1936. Moss Flora of North America, North of Mexico. Vol. 1. Newfane, Vermont.
    Hilferty, F. J. 1960. The mosses of Massachusetts. A county catalogue with annotations. Rhodora 62: 145--173.
    Ketchledge, E. H. 1980. Revised checklist of the mosses of New York State. New York State Mus. Bull. 440.
    Lampton, R. K. 1970. Mosses of Georgia. A check list of species which have been collected within the State. Bull. Georgia Acad. Sci. 28: 81--98.
    Mahler, B. D. and W. F. Mahler. 1980. Checklist of mosses of Oklahoma. Bryologist 83: 202--208.
    McCleary, J. A. and P. L. Redfearn, Jr. 1979. Checklist of the mosses of Illinois. Trans. Illinois State Acad. Sci. 72: 28--51.
    Norris, D. H. and J. R. Shevock. 2002. Contributions toward a bryoflora of California: A specimen based catalogue of mosses. Unpublished manuscript.
    Redfearn, P. L., Jr. 2001. Checklist of the mosses of the interior highlands of North America in Arkansas, Illinois, Missouri and Oklahoma. 62 pp. Southwest Missouri St. Univ., Springfield.
    Robinson, H. and C. F. Reed. 1987. Notes on the distribution of the Bartleya expression of Dicranella cerviculata in Appalachian coal fields. Bryologist 90: 43--44.
    Snider, J. A. and B. K. Andreas. 1996. A catalog and atlas of the mosses of Ohio. Ohio State Univ., Columbus.
    Snider, J. A., S. M. Studlar and M. Medley. 1986. A Checklist of Bryophytes of Kentucky. Flora Online 15.
    Whitehouse, E. and F. McAllister. 1954. The mosses of Texas. A catalogue with annotations. Bryologist 57: 63--146.
    Wilkes, J. C., Jr. 1965. A check list of the mosses of Alabama. J. Alabama Acad. Sci. 36: 75--93.
    Worley, I. A. and Z. Iwatsuki. 1970. A checklist of the mosses of Alaska. Bryologist 73(1): 59--71.


    1 Capsule subglobose; peristome teeth less than 180 µm, shortly and irregularly 2-fid, papillose (subg. Microdus).   Dicranella lindigiana
    + Capsule elongate; peristome teeth 250--500 µm, 2-fid to the middle or proximally, vertically pitted-striolate at base (subg. Dicranella).   (2)
           
    2 (1) Seta yellow.   (3)
    + Seta red.   (5)
           
    3 (2) Capsule erect, smooth; perichaetial leaves not sheathing; leaves often blunt or rounded at a narrow apex.   Dicranella hilariana
    + Capsule suberect to nodding, furrowed; perichaetial leaves sheathing at base; leaves acute.   (4)
           
    4 (3) Leaves serrulate in distal half; distal cells short-rectangular (2--4:1); capsule suberect, not curved, oblique at the mouth, not strumose.   Dicranella heteromalla
    + Leaves serrulate at the apex and sometimes also at shoulders; distal cells long-rectangular (5--10:1); capsule nodding, curved, not oblique mouthed, strumose.   Dicranella cerviculata
           
    5 (2) Perichaetial or both stem and perichaetial leaves with obovate, sheathing bases and spreading to squarrose limbs.   (6)
    + Perichaetial leaves scarcely differentiated from stem leaves; leaves wide-spreading to secund, not squarrose.   (9)
           
    6 (5) Costa long-excurrent; leaf cells long-rectangular, 6--8:1; annulus present.   (7)
    + Costa short-excurrent; leaf cells short and broad, some cells only 2--3:1; annulus lacking.   (8)
           
    7 (6) Leaves squarrose distally, spreading-flexuose proximally; capsule erect and symmetric.   Dicranella crispa
    + Leaves erect to falcate-secund; capsule inclined or nodding.   Dicranella subulata
           
    8 (6) Leaves long-decurrent, oblong-lanceolate, obtuse to rounded at the apex, entire.   Dicranella palustris
    + Leaves not decurrent, narrowly lanceolate, acute or obtuse, entire to irregularly toothed at apex.   Dicranella schreberiana
           
    9 (5) Leaf margins plane, sinuate-dentate; capsule erect and symmetric.   Dicranella rufescens
    + Leaf margins recurved, at least in part, entire except at the apex; capsule inclined, asymmetric.   (10)
           
    10 (9) Leaves 2-stratose and incurved distally, subtubulose; distal cells 1--2:1.   Dicranella pacifica
    + Leaves not 2-stratose, erect or ± incurved distally, but scarcely subtubulose; distal cells 6--9:1.   Dicranella varia

  • List of lower taxa


     

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