|
BFNA Title: Rhodobryum |
|
RHODOBRYUM –
BRYACEAE XX. RHODOBRYUM
(Schimper) Limpricht, Die Laubmoose Deutschlands, Oesterreichs und der
Schweiz 2: 444. 1892 * [Greek rhodo, rose, and Bryum, a moss genus] John Spence Plants large for the family, dark green or olive-green, sometimes with red tints. Stems secondary to 6 cm, erect, arising from wiry creeping stoloniferous primary stems, unbranched or sometimes innovations arising from below the terminal rosette; rhizoids sparse to abundant, at base of stem or arising as macronemata in leaf axils, micronemata lacking on leafy stems. Leaves small and scale-like proximally, becoming enlarged distally and crowded in a terminal rosette, 4--12 mm, strongly contorted and shrunken when dry, erect-spreading when moist; margins bordered by elongate thickened cells or sometimes border weak or absent, 1-stratose, strongly serrate from mid leaf to apex; distal and median laminal cells hexagonal to rhomboidal, 3--4:1, proximal laminal cells elongate-rectangular, longer than distal cells, alar cells not differentiated; costa typically strong, subpercurrent to more often percurrent to short excurrent as a short and often recurved hairpoint or apiculus, in cross section with 2--4 layers of enlarged guide cells, stereid band small or absent. Specialized asexual reproduction lacking. Sexual condition dioicous; inner perichaetial leaves somewhat differentiated, smaller and narrower than surrounding rosette leaves; inner perigonial leaves small, broad, over-arching enlarged disc-like pale perigonia with abundant paraphyses. Seta 1--8 per perichaetium, red or brown, long-exserted, 2--5 cm, straight to slightly flexuose. Capsule inclined to nutant, brown to red-brown, oblong to cylindric, 3--5 mm, slightly curved and narrowed to mouth, mouth sometimes oblique; operculum low-conic; peristome double, well-developed, exostome teeth lanceolate, acuminate, brown or yellow-brown proximally, hyaline near apex; endostome with high basal membrane, segments lanceolate to subulate, keeled and perforate, cilia 2--4, nodose to appendiculate. Spores 10--22(--25) \um, finely papillose.Species ca. 25
(2 in the flora): worldwide in temperate to tropical regions, all continents
except Rhodobryum is a genus characterized by relatively
large plants with leaves in a distinct rosette (at least in the region of the
flora), stoloniferous primary stems, guide cells in two or more layers, and
reduced stereid band in the costa. The
chromosomes of Rhodobryum are
distinctly different from those of Bryum
and Rosulabryum (H. P. Ramsay and
J. R. Spence 1996). Like Roellia and Rosulabryum, more than one sporophyte can mature from the same
perichaetium. Roellia differs from Rhodobryum
by its lack of stolons, less contorted shiny pale green leaves that are
finely rugose, and much larger laminal cells.
Robust specimens of Rosulabryum
andicola and R. canariense
differ in their strongly developed stereid band with a single layer of guide
cells, smaller leaves, lack of stolons, and presence of rhizoidal tubers and
filiform leaf-axis gemmae. Most
species of Rhodobryum occur in the
tropics, especially in montane regions.
Recent DNA research suggests that the genus, excepting only Leptostomopsis, is basal to and sister
to the remainder of the Bryaceae. SELECTED REFERENCES Iwatsuki,
Z. and T. Koponen. 1972. On the taxonomy and distribution of Rhodobryum roseum and its related
species (Bryophyta). Acta Bot. Fennica 96: 1--22. Koponen, T., X. Li and M.
Zang. 1982. A synopsis of Rhodobryum
(Musci, Bryaceae) in 1. Rosette
leaves typically 18--55 in number, leaf margins strongly revolute to mid leaf
or well beyond, stereid band relatively well developed, reaching dorsal
epidermal cells, without layer of thin-walled cells between. 1. Rhodobryum
ontariense 1. Rosette
leaves typically 15--21 in number, leaf margins weakly recurved to about
mid-leaf, stereid band small, with at least one distinct layer of thin-walled
cells before dorsal epidermal cells. 2.
Rhodobryum roseum 1. Rhodobryum ontariense (Kindberg) Kindberg, Spec. Eur. N.
Amer. Bryin. II: 346. 1897 Plants 1--5 cm tall, mostly unbranched or
rarely with slender sub-apical innovations. Stem leaves 4--10 mm, numerous in rosettes, from 18--55,
typically more than 20; margins strongly
revolute to above mid leaf, often nearly to apex, apex broadly acute
to cuspidate; costa percurrent to short-excurrent into a slender hairpoint in
rosette leaves, in cross section with distinct stereid band, reaching dorsal
epidermal layer without intervening thin-walled layer of cells; distal and
median laminal cells hexagonal, 25--35 ×
50--80 \um, (3--4:1), proximal cells longer, to 100 \um, rectangular. Inner perichaetial leaves with costa
strong, long-excurrent in denticulate hairpoint. Spores 16--24 µm. Capsules
mature late winter--late fall (Feb.--Nov.). Common on rich soil in forests,
along forest edges, on rotten logs, tree bases, soil over rock or rock, often
calcareous, sometimes in boggy sites; 0--3000 m, restricted to higher
elevations in southern latitudes; Alta, Man., N.B., Nfld., N.S., Ont., Que.,
Sask.; se Ariz., Ark., Conn., Del., D.C., n Ga., Ill., Ind., Iowa, Kans.,
Ky., Maine, Md., Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Mex., N.Y.,
N.C., N.Dak., Ohio, Pa., R.I., n S.C., S.Dak., Tenn., w Tex., Vt., Va.,
W.Va., Wis.; Mexico; Eurasia; Asia (India, Japan, mainland southeast Asia). This is a
common and characteristic species of the eastern deciduous forests, occurring
as far south as 2. Rhodobryum roseum (Hedwig) Limpricht, Laubm. Deutschl.
3: 444. 1892 Plants 1--3 cm tall, commonly branched by
slender sub-apical innovations. Stem
leaves 3--8 mm, relatively few in rosettes, 18--22; margins revolute to
about mid leaf or less, apex acute; costa variable, from subpercurrent to
percurrent, with slender apiculus, to short-excurrent into a slender
hairpoint on median rosette leaves, in cross section with small stereid band,
not reaching dorsal epidermal layer because of a layer of intervening
thin-walled cells; distal and median laminal cells hexagonal, 25--35 × 50--80 \um, (3--4:1), proximal cells longer, to 100 µm,
rectangular. Inner perichaetial leaves
with costa variable, from subpercurrent to percurrent or excurrent into a
short, smooth to weakly denticulate hairpoint. Spores 16--20 \um. Capsules
mature late summer (Jul.--Sep.). Rare, rich soil, humus and litter in coastal
tundra and shrublands or occasionally forests; 0--300 m; B.C.; This species
is found only in coastal and near-coastal regions of |
