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Dicranum majus

(Dicranum Moss)

Common Names

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Common Names in English:

Dicranum Moss

Description

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Family Dicranaceae

Plants small to large, often in dense tufts. Stems erect , simple or dichotomously to irregularly branched, usually with central strand, often densely radiculose , tips occasionally deciduous. Leaves in several rows around the stem, erect or secund , often falcate-secund, sometimes crispate , short- to long-lanceolate, whole leaves or their tips sometimes deciduous; costa single, usually strong , percurrent to excurrent, sometimes ending in a short to long hyaline awn , smooth , ridged or lamellose on abaxial surface, rhizoids occasionally on adaxial or abaxial surface near leaf base ; laminal cells smooth or sometimes distal cells mammillose or papillose on one or both sides, papillae rarely forked , or toothed by projecting cell ends, pitted or nonpitted; proximal cells elongate , often differentiated in alar region, sometimes undifferentiated. Specialized asexual reproduction absent or occasionally present as brood leaves, microphyllous branches, borne in axils of distal leaves or as rhizoidal tubers. Sexual condition autoicous , dioicous or pseudomonoicous. Seta solitary or several per perichaetium , elongate, usually straight, sometimes flexuose or cygneous . Capsule exserted, erect, inclined , or sometimes curved , cylindrical or ovoid , smooth, ridged, furrowed or irregularly wrinkled, sometimes strumose ; stomata present or absent, superficial; annulus present or absent, often compound , deciduous or persistent ; operculum conic or obliquely rostrate from a conic base; peristome single, usually of 16 lanceolate teeth, deeply divided into 2 or rarely 3 divisions, usually vertically striolate or pitted-striolate proximally, papillose distally. Calyptra cucullate , smooth, naked, sometimes fringed at base, usually covering most of capsule, fugacious . Spores mostly spheric, smooth to papillose.

Genera 50-52, species ca. 900 (17 genera, 90 species in the flora ) : worldwide.

Distinctive characters of this large acrocarpous family include the erect, often tomentose stems; mostly narrow, lanceolate, occasionally falcate or falcate-secund leaves, with a single, narrow to broad costa, with or without rhizoids at the base, sometimes ending in a hyaline, occasionally toothed apex, costa in cross section with or without stereid bands , leaf cells usually smooth, sometimes mammillose, or rarely with a single papilla on one or both sides, papillae rarely forked, asexual propagation by specialized deciduous branches, deciduous leaves or leaf apices, rarely rhizoidal tubers; sporophytes usually solitary or rarely clustered, setae mostly elongate, straight or rarely flexuose or cygneous, capsule cylindric to ovoid, erect to horizontal, smooth or ribbed , sometimes strumose, operculum usually obliquely rostrate, peristome single, with 16 teeth often divided 1/2 way to the base, usually striolate or pitted-striolate proximally, papillose distally.[1]

Genus Dicranum

Plants in loose to dense tufts, yellowish green to dark green, dull or shiny. Stems (0.5-) 2-12(-18) cm, erect , simple or forked , densely tomentose with white or reddish brown, smooth to papillose rhizoids, these sometimes nearly absent, rhizoids arising at bases of branches (macronemata) and sometimes in rows scattered along stems (micronemata). Leaves usually lanceolate, rarely ovate , proximal part concave , rarely flat, distal subula keeled to tubulose , erect-appressed, erect-patent or spreading , straight, weakly curled, crispate or cirrate when dry, generally falcate-secund, less often straight, undulate , rugose or smooth; apices acute to obtuse , tips sometimes deciduous, apparently a means of asexual reproduction; margins plane to incurved or involute , entire to serrate in distal part, entire proximally; laminae 1- or 2-stratose at margins or sometimes near costa; laminal cells smooth; costa single, ending before apex to excurrent, smooth or toothed on abaxial surface, sometimes with 2-4 serrated ridges abaxially, 1-2 rows of guide cells, two well-developed stereid bands above and below, sometimes slightly differentiated or absent, extending to apex, or ending before the apex, adaxial and (or) abaxial epidermal layers of cells differentiated or undifferentiated, sometimes only a few cells in both layers enlarged; laminal cell walls weakly to strongly bulging, or bulges absent; leaf cells pitted or nonpitted, smooth or sometimes abaxially, rarely adaxially, mammillose , papillose or toothed by projecting cell ends, walls often thickened; distal and median laminal cells short or long, quadrate , rectangular or irregularly angled , proximal cells rectangular to linear , alar cells inflated , 1- or 2-stratose, rarely more, generally orange to brown, rarely poorly differentiated. Specialized asexual reproduction absent or as clusters of 1-6, deciduous, terete , flagelliform branchlets , borne in axils of distal leaves. Sexual condition dioicous or pseudomonoicous; male plants as large as female plants or dwarfed and epiphytic on stem rhizoids of female plants; perigonial leaves ovate, concave, short-acuminate; perichaetial leaves usually convolute-sheathing, abruptly subulate or rarely interior leaves gradually acuminate. Seta solitary or up to 6 per perichaetium , smooth, elongate , erect, twisted when dry, yellow, brown or reddish. Capsule erect or inclined , cylindric , straight or arcuate , smooth, striate or furrowed when dry, annulus of 1-3 rows of usually large, deciduous or persistent cells, sometimes indistinctly differentiated; operculum long-rostrate, straight or arcuate; peristome single, 16 teeth, split 1/3-1/2 their length into 2, rarely 3, divisions, vertically pitted-striolate proximally, papillose above, reddish brown. Calyptra cucullate , smooth, naked, covering most of capsule, fugacious . Spores 12-30 µm, spherical , finely papillose.

Species ca. 140: North America, Mexico, West Indies, Central America, South America, Europe, Asia, Africa, Australia.[2]

Physical Description

Species Dicranum majus

Plants in loose tufts, green to light green, glossy to somewhat dull . Stems 3-16 cm, naked or with a few whitish rhizoids, rarely moderately tomentose , rhizoids (micronemata) in rows above each leaf. Leaves somewhat sparse, falcate-secund or erect-patent, flexuose or straight, little changed when dry, usually smooth , (6-) 8-11.5(-15) × 1-2 mm, concave proximally, tubulose above, from a lanceolate to ovate-lanceolate base , gradually narrowed to a long, falcate-secund or straight, acute apex; margins serrate in the distal half, sometimes slightly serrulate above to almost entire ; laminae 1-stratose or with few 2-stratose regions on or near the margins; costa percurrent to shortly excurrent, 1/12-1/7 the width of the leaves at base, toothed distally or serrulate to nearly smooth on abaxial surface, with a double row of guide cells that is sometimes interrupted , two stereid bands extending to apex, adaxial epidermal layer of cells with some cells differentiated, the abaxial layer completely differentiated; cell walls between lamina cells not bulging; leaf cells smooth or abaxially prorate or toothed above; alar cells 2-stratose or multistratose, well-differentiated, not extending to costa; proximal laminal cells elongate , pitted , (42-) 71-112(-140) × (5-) 9-10(-15) µm; distal laminal cells shorter, linear to oval , pitted, (42-) 47-61(-99) × (7-) 10-11(-17) µm. Sexual condition pseudomonoicous; dwarf males among rhizoids of female plants ; interior perichaetial leaves abruptly long-acuminate, convolute-sheathing. Seta 2.5-5 cm, aggregate, 2-5 per perichaetium , rarely solitary, yellow to light brown. Capsule 2-3.5 mm, arcuate , inclined to horizontal, smooth to faintly striate when dry, dark brown or yellowish brown; operculum 2-3 mm. Spores 14-19 µm. [source]

Dicranum majus is the only North American species of the genus with a double row of guide cells. It is a distinctive species with oceanic tendencies and in North America it commonly grows in northern coastal localities on both sides of the continent, occasionally occurring inland in very moist habitats . [source]

Habit: Nonvascular

Habitat

 

Taxonomy

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Ambiguous Synonyms

  1. Dicranum polysetum Bridel, 1806

Notes

Name Status: Accepted Name . Latest taxonomic scrutiny: 19-Jul-2004

Similar Species

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Members of the genus Dicranum

There are approximately 510 species in this genus. Here are just 100 of them:

D. acanthoneurum · D. aciculare · D. aciphyllum · D. acrocaulon · D. acutifolium (Acuteleaf Dicranum Moss) · D. adianthoides · D. affine · D. albescens · D. albicans · D. albidum · D. albulum · D. algidum · D. alopecurus · D. alpestre · D. altissimum · D. alto-filifolium · D. amabile · D. anderssonii · D. angustatum · D. angustifolium · D. angustinerve · D. angustirete · D. angustum (Dicranum Moss) · D. aquaticum · D. araucarieti · D. arcticum · D. arctocarpum · D. arcuatipes · D. arcuatum · D. asperrimum · D. asperulum · D. assamicum · D. assimile · D. atratum · D. attenuatum · D. aucklandicum · D. australe · D. austro-congestum · D. austro-georgicum · D. bartramianum · D. bentzelii · D. bergeri (Undulate Dicranum Moss) · D. billardierei · D. billardieri · D. bipartitum · D. blindioides · D. blumii · D. blyttii · D. bolivianum · D. bonjeani · D. bonjeanii (Bonjean's Dicranum Moss) · D. bonjeanii subsp. latifolium · D. borbonicum · D. boswellii · D. brachycaulon · D. brachymitrium · D. brachypelma · D. brachyphyllum · D. braunii · D. braunsiae · D. breviflagellare · D. brevifolium (Shortleaf Dicranum Moss) · D. brevisetum · D. bryoides · D. bullatum · D. cacuminis · D. caesium · D. caespitosum · D. calymperaceum · D. calymperidictyon · D. calymperoideum · D. camptophyllum · D. campylophyllum · D. canadense · D. canaliculatum · D. canariense · D. canescens · D. capitiflorum · D. carneum · D. caudatum · D. cerviculatum · D. cheoi · D. chionophilum · D. chlorocladum · D. chlorophyllosum · D. chrysodictyon · D. circinatum · D. cirrifolium · D. clathratum · D. collinum · D. compactum · D. comptum · D. condensatum (Condensed Dicranum Moss) · D. confine · D. congestiforme · D. congestum · D. congestum Brid. var. divaricatum Herzog · D. congestum flexicaule · D. consobrinum · D. contortum

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 27, 2008:

Identifiers

Footnotes

  1. Robert R. Ireland Jr. "Dicranaceae". in Flora of North America Vol. 27 Page 12, 39, 331, 358, 360, 426, 427, 433, 440, 443, 444, 548, 564. Oxford University Press. Online at EFloras.org. [back]
  2. Robert R. Ireland Jr. "Dicranum". in Flora of North America Vol. 27 Page 9, 10, 26, 32, 33, 38, 359, 360, 362, 386, 397, 398, 405, 406, 411, 420,. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 2009-04-24