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BFNA Title: Rhizogoniaceae XXX. RHIZOGONIACEAE
Brotherus Steven P. Churchill Plants small to large, in loose to dense
tufts. Stems erect or curved,
few branched; central strand well developed; radiculose, often densely
tomentose. Leaves spirally
arranged or appearing 2-ranked, distant or rather crowded, ovate to narrowly
or broadly oblong-lanceolate to linear-lanceolate, apex acute to acuminate,
base decurrent or not; margins plane or reflexed to recurved, crenulate,
dentate or sharply serrate, teeth single and margins 1-stratose or double and
margins 2-stratose; 1-costate, strong, percurrent to short-excurrent, toothed
abaxially distally or smooth; laminal cells mostly isodiametric and smooth or
bulging mammillose, walls firm and entire; alar region undifferentiated. Specialized asexual reproduction
lacking or present, in leaf axils of distal stems and branches,
cylindrical. Sexual condition:
synoicous, autoicous, or dioicous. Perigonia
bud-like, usually below perichaetia. Perichaetia
lateral, at base or at mid stem, leaves small and differentiated. Seta elongate, smooth. Capsule horizontal to erect, short
to long-cylindrical, symmetric to asymmetric, curved or straight; opercula
conic, short to long-rostrate, oblique; peristome double or absent, exostome
teeth 16, cross-striate proximally, papillose distally or papillose
throughout; endostome basal membrane moderately high, segments 16, keeled,
perforate, cilia usually present, 2--3.
Calyptra cucullate. Spores
spherical, lightly papillose. Genera
8, ca. 40 species (1 genus, 1 species in the flora): tropical to subtropical
with a distinct circum-southern temperate element. The
distinguishing feature of the Rhizogoniaceae is the position of the
sporophytes, occurring in the basal half or at the base of the erect stems.
For the purpose of this treatment a somewhat traditional circumscription of
the Rhizogoniaceae has been maintained. The family has been re-analyzed by T.
Koponen (1988). This new view of the family may represent a monophyletic
group. The cladogram, however, is not well corroborated and further
investigation is needed; under that classification Pyrrhobryum would
be placed in the Mniaceae. SELECTED
REFERENCES Inoue, S. and Z.
Iwatsuki. 1976. A cytotaxonomic study of the genus Rhizogonium Brid. (Musci). J. Hattori Bot. Lab. 41: 389--403. Koponen, T. 1988.
The phylogeny and classification of Mniaceae and Rhizogoniaceae
(Musci). J. Hattori Bot. Lab. 64: 37--46. Manuel, G. 1980.
Miscellanea Bryologica II. Classification of Rhizogonium Brid., Penzigiella
Hookeri Gangulee, and some nomina
nuda. Cryptog., Bryol. Lichénol. 1: 67--72. 1.
PYRRHOBRYUM Mitten, J. Linn. Soc.,
Bot. 10: 174. 1868 * [Greek pyrrho, flame-colored, tawny, red,
yellowish-red, and bryon, moss] Stems with exterior 2--3 rows of cells small,
thick-walled, interior cells larger, moderately thick-walled; rhizoids often
forming a dense tomentum below. Leaves
distant [to crowded], linear-lanceolate [to broadly lanceolate], margin
doubly-serrate to near base, apex acuminate; costa abaxially toothed [or
smooth], transverse section with stereid cells well developed on both side of
guide cells; juxtacostal basal cells often weakly differentiated, enlarged,
short to rather long-rectangular, lax or not; medial and distal laminal cells
uniform throughout, cells isodiametric, rounded to 4--6 sided, thick-walled,
smooth; marginal laminal cells 2-stratose. Seta wiry. Capsule
inclined to horizontal, usually curved, cylindric, becoming striate and
flared at the mouth when deoperculate; exothecial cells quadrate- to
rectangular-rounded, moderately thick-walled, somewhat weakly collenchymatous
at base; stomates few at base, superficial. Species
10 (1 in the flora): pantropical and south temperate areas. The
genus is characterized by the elongate stems, distal and spirally arranged broadly
to narrowly lanceolate or linear-lanceolate leaves, doubly toothed,
2-stratose leaf margins, costa distally toothed abaxially, mostly
isodiametric laminal cells alike to near base, and sporophyte positioned
somewhat midway on stem or at the base. SELECTED
REFERENCE. Frahm, J.-P., K. Rembold, T. Röver and T. Schamell. 2003. Synopsis
der Gattung Pyrrhobryum (Musci, Rhizogoniaceae). Trop. Bryol. 24:
115--127. 1.
Pyrrhobryum spiniforme (Hedwig)
Mitten, J. Linn. Soc., Bot. 10: 174. 1868 Hypnum spiniforme Hedwig, Sp. Musc. Frond. 236. 1801; Mnium spiniforme (Hedwig) J. K. A.
Müller; Rhizogonium spiniforme (Hedwig)
Bruch Plants often appearing feathery, in loose
tufts, dark green and glossy, occasionally yellowish green or brown with
age. Stems erect, sometimes
curved or curled, to 6 cm or more, solitary or occasionally branched, often
grooved below; densely tomentose at base (to ca. 5 mm from base), rhizoids
dark rusty-red, papillose. Leaves
distant on stem, crispate and curled when dry, erect-spreading to
wide-spreading when wet, linear to linear-subulate, (5--)6--8 ´
0.40--0.75 mm, somewhat concave or folded, apex often terminating in a double
tooth, base undifferentiated or occasionally indistinctly decurrent; margins
plane, slightly recurved at base, in
transverse section 2-stratose, 1-stratose at base; laminal cells uniformly
subquadrate to short-rectangular, (7--)10--14 µm; marginal basal cells
quadrate to rectangular, 14--30 ´ 10 µm. Seta pale yellowish orange or straw-colored, 4--6
cm. Capsule
ellipsoid-cylindric, (1.5--)2--3 mm, neck short; exothecial cells hexagonal,
thick-walled; stomata several at urn base and neck; operculum 1.5--2 mm,
oblique; exostome teeth reddish orange basally, pale yellow or hyaline
distally, endostome segments pale yellow or hyaline, lightly papillose. Calyptra ca. 3.5 mm. Spores 16--18 µm. Capsules
mature Dec.--Apr. Forest, base of tree trunks, logs, soil; Ala., Fla., Ga.,
La., Miss.; Mexico; West Indies; Central America; South America; Asia;
Africa; Pacific Islands; Australia. This species
is characteristic of the southeastern U.S.A. coastal region. |
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