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BFNA Title: Plagiobryoides |
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XX. PLAGIOBRYOIDES J. R.
Spence, Phytologia 87: 24, 2005 * [Greek oides,
similarity, and Plagiobryum] John R. Spence Plants small
to large, in dense turfs, green, yellow-green, red-brown, pink or red. Stems short to elongate, 0.5--4 cm,
evenly foliate, not or rarely weakly julaceous, not or weakly branched,
stolons absent; rhizoids scarce, micronemata and macronemata absent from
stems or present in clusters on proximal stem. Leaves crowded to distant on stems, somewhat contorted when dry,
erect to erect-spreading when wet, broadly ovate to ovate-lanceolate, flat to
concave, 0.3--3(--3.5) mm, base straight or slightly curved at insertion,
usually red, decurrent or not; margins plane or sometimes recurved
proximally, 1--3 stratose, more or less smooth, limbidium present, of
elongate cells or absent, apex broadly rounded to acute, not hyaline, costa
not reaching apex to very short-excurrent in smooth point, costa transverse
section with stereid band single, usually well developed, guide cells absent
or sometimes present proximally; adaxial supracostal cells irregularly to
regularly elongate-rectangular at base, laminal cells somewhat heterogeneous,
wide, mostly more than 16 \um wide, proximal cells usually long-rectangular,
sometimes bulging, 4--6:1, medial cells generally similar to distal cells,
distal cells highly variable, irregularly rhomboidal, 2--4:1, near tip
sometimes more or less quadrate, not in rows oblique to the costa,
thin-walled, walls not pitted, alar cells not differentiated from juxtacostal
cells. Specialized asexual
reproduction of rhizoidal tubers on rhizoids at base of stem and in
proximal leaf axils. Sexual condition
dioicous or rarely synoicous, perigonia and perichaetia terminal, leaves the
same size as vegetative leaves or typically larger, not forming a rosette,
inner leaves little differentiated. Seta
1, straight to flexuose or twisted, rarely geniculate. Capsule inclined to suberect, 2--6 mm, elongate-pyriform,
apophysis differentiated or not, often elongate, mouth often oblique, exothecial
cells near mouth quadrate or short-rectangular, thick walled, reddish, in
1--4 rows, cells below longer, irregularly
long-rectangular with straight or sinuose walls; annulus usually
present, revoluble; operculum weakly convex, short-conic, not rostrate;
peristome double, exostome pale yellow or tan proximally, hyaline distally,
teeth lanceolate, trabeculate, lacking pores along fissural line, endostome
hyaline to pale yellow, separate from exostome or sometimes adherent, basal
membrane high, segments narrowly to broadly perforate, rarely longer than
exostome, rarely absent, cilia present or more commonly absent. Calpytra fugacious, cucullate, small,
smooth. Spores shed singly, not as
tetrads, not germinating in capsule, 11--30 \um, finely papillose, pale
brown, tan or yellow-tan. Species 15 (6 in flora);
tropical to warm temperate regions of the world, with concentrations in the
Neotropics and southeast Asia. Plagiobryoides is similar to Plagiobryum in gametophyte
structure, but has a more or less symmetric capsule with the endostome
typically shorter than the exostome, and spores that are shed singly. The two
genera are probably closely related, with primary speciation of Plagiobryum
in Arctic-alpine regions of the northern hemisphere and Plagiobryoides
in the tropics. Molecular studies are not available for these taxa and for the
morphologically similar Haplodontium. Although the genus was
originally described for the highly unusual Plagiobryoides
incrassatolimbata, the overall leaf structure, especially the laminal
areolation, is similar for this and the other species, with typically very
broad thin-walled cells, becoming very long proximally, while the capsules
are also similar in overall shape. As
in Plagiobryum, the endostome segments can sometimes be longer than
the exostome teeth, especially in some populations of Plagiobryoides
cellularis. Several of our species have only recently been collected in
the flora region, and are quite rare. B. Allen (2002) provided valuable
information on the Neotropical species. SELECTED REFERENCES Andrews, A.
L. 1935. Bryaceae. In: A. J. Grout. Moss flora of 1. Stems
elongate, to 4 cm, leaves distant, often red to red-brown, decurrent, apex
rounded, strong 2- to
multi-stratose limbidium present, rhizoidal tubers absent ...... 3. Plagiobryoides incrassatolimbata 1. Stems short
to medium length, 0.5--2 cm, leaves crowded or distant, pale pink, green,
yellow-green or yellow-brown, not or only weakly decurrent, apex rounded or
acute, limbidium present or absent, 1-stratose, large rhizoidal tubers
sometimes present at base of stem. 2.
Rhizoidal tubers absent; synoicous; peristome reduced, exostome segments
irregular, often short, endostome adherent to exostome, fragile, cilia
absent, spores 18--22 \um .............. 1. Plagiobryoides brachyneura 2.
Rhizoidal tubers sometimes present; dioicous; peristome well developed,
exostome teeth long, endostome not adherent, cilia present or sometimes
absent, spores 12--30 \um. 3.
Leaf apex broadly rounded, costa not reaching apex, leaves concave, somewhat
decurrent .......... 5. Plagiobryoides renauldii 3.
Leaf apex acute, costa not reaching apex to short-excurrent, leaves not or
weakly concave, not decurrent. 4. Distinct limbidium present, distal leaf margins sharply
serrate, leaves sometimes weakly complanate .................... 4. Plagiobryoides
limbata 4. Limbatum mostly absent, distal leaf margins smooth, leaves
never complanate. 5.
Distal lamina cells elongate, (2--)3--4:1, plants pale pinkish green, leaves
imbricate when dry, rhizoidal tubers absent; capsule with a distinct
elongated apophysis ............ 2. Plagiobryoides cellularis 5.
Distal lamina cells often short and broad, some quadrate, 1--2(--3):1, plants
bright green, leaves contorted when dry, rhizoidal tubers sometimes present
capsule with a short indistinct apophysis .................... 6. Plagiobryoides vinosula 1. Plagiobryoides brachyneura (Kindberg) J. R.
Spence, Phytologia 91: 498. 2009 C E Bryum brachyneuron Kindberg, Ottawa
Nat. 5: 179. 1892 Plants in dense turfs, green or yellow-green. Stems short to elongate, 0.5--2 cm, not julaceous, somewhat
branched, innovations common; rhizoids common on proximal portions of stem. Leaves somewhat contorted when dry,
crowded along stem, erect to erect-spreading when wet, narrowly to broadly
ovate, flat or weakly concave, 0.5--2(--3.5) mm, not decurrent, base red;
margins plane or recurved proximally, 1-stratose, more or less smooth,
limbidium variable, absent on younger leaves to present on older leaves, apex
broadly acute, not hyaline, costa not reaching apex to very short-excurrent
in smooth point, leaves of innovations smaller with more obtuse apex and
weaker costa, laminal cells somewhat heterogeneous, distal cells irregular in
shape, 35--50 x 18--25 \um, 1--3:1, cells incrassate, proximal cells
rectangular, (50--)60--80 x 18--28 \um, 3--5:1, sometimes bulging. Specialized asexual reproduction absent. Sexual condition synoicous. Seta
short, thick, red-brown, (0.5--)1--1.5 cm, flexuose to sometimes geniculate. Capsule inclined to nutant, 2--4 mm,
brown, elongate-pyriform, hypophysis strongly differentiated, elongate,
operculum weakly convex, conic, apiculate; peristome double, exostome pale
yellow or tan proximally, hyaline distally, teeth blunt to lanceolate,
irregular in shape, endostome hyaline to pale yellow, adherent to exostome,
basal membrane high, segments absent or occasionally a few present,
perforations narrow, cilia absent. Spores
18--22 \um, papillose, dark yellow-brown. Capsules mature summer (Jul--Aug.).
Rare, damp to seepy rock faces or crevices; 0--100 m, Plagiobryoides pachyneura is very distinctive, with
elongate-necked capsule, very short twisted seta, and short broad distal laminal
cells. A. L. Andrews (1935) suggested that P. brachyneura is similar
to species of Plagiobryum. The combination of gametophyte and sporophyte
characters indicates a relationship with P. cellularis and its allies,
thus I have transferred the species to Plagiobryoides. It should be sought for elsewhere in the
Bering Sea region, especially in the Aleutian Islands and 2. Plagiobryoides cellularis
(Hooker) J. R. Spence,
Phytologia 91: 498. 2009 Bryum cellulare Hooker, Sp. Musc. Frond., Suppl. 3: 1(1): 214:
a. 1827. Plants in dense short turfs, pale pink-green. Stems short, 0.5--1 cm, weakly julaceous, somewhat branched,
innovations common; rhizoids sparse on proximal stem. Leaves mostly imbricate when dry, erect when wet, crowded along
stem, narrowly to broadly ovate, flat or weakly concave, 0.4--1(--2.5) mm,
not decurrent, base pink; margins plane or recurved proximally, 1-stratose,
more or less smooth, limbidium absent or rarely a single indistinct layer of
elongate cells present proximally, apex acute, costa reaching apex to very short-excurrent
in smooth point, leaves of innovations smaller with more obtuse apex and
weaker costa, laminal cells somewhat heterogeneous, distal cells elongate
hexagonal, 30--70 x 16--22 \um, 2--4:1, cells thin-walled, proximal cells
long rectangular, (60--)80--100 x 18--24 \um, 4--5:1, sometimes bulging, thin-walled. Specialized asexual reproduction
absent. Sexual condition dioicous.
[Seta short, thick, red-brown, (1--)2--3
cm, flexuose to twisted. Capsule
inclined to nutant, 2--4 mm, brown, elongate-pyriform, hypophysis strongly
differentiated, elongate, operculum weakly convex, conic, apiculate;
peristome double, exostome pale yellow or tan proximally, hyaline distally,
teeth lanceolate, endostome hyaline to
pale yellow, not adherent to exostome, basal membrane high, segments present,
sometimes longer than exostome, perforations narrow, cilia usually absent,
occasionally 1--2 present. Spores
20--28 \um, papillose, yellow-brown.] Rare on damp to seepy rock; 10 m,
Fla.; Mexico; West Indies; Central America; South America; tropical Africa; se
Asia; Australia; Pacific Islands (Indonesia, New Guinea). . A
widespread pantropical species. Our material is very poor, consisting of a
few small sterile shoots from rocks near the sea on the 3. Plagiobryoides incrassatolimbata (Cardot) J. R.
Spence, Phytologia 87: 24. 2005 Bryum incrassatolimbatum Cardot, Rev. Bryol.
36: 114. 1909 Plants in dense turfs, dark green, olive-green, or more commonly dark red,
red-brown or brown. Stems short to
long, 1--3(--4) cm, not julaceous, somewhat branched, innovations common;
rhizoids sparse on proximal stem. Leaves
somewhat contorted when dry, erect to erect-spreading when wet, somewhat crowded
along stem, narrowly to broadly ovate, concave, 1--2(--3) mm, longly
decurrent, base red; margins plane, multistratose, more or less smooth,
limbidium of short cells in (1--)2--4 layers, apex broadly acute to obtuse,
costa not reaching apex to rarely percurrent, leaves of innovations smaller
with more obtuse apex and weaker costa, laminal cells somewhat heterogeneous,
distal cells irregularly rhomboidal, 35--60 x 12--24 \um, 1--3:1, cells thin-walled,
proximal cells rectangular, (60--)80--100 x 18--28 \um, 3--5:1, sometimes bulging, thin-walled. Specialized asexual reproduction
absent. Sexual condition dioicous.
Seta slender, red-brown, 1--1.5
cm, flexuose to sometimes geniculate. Capsule suberect, 2--3 mm, brown,
elongate-pyriform, hypophysis weakly differentiated, relatively short,
operculum weakly convex, conic, not apiculate; peristome double, exostome
pale yellow proximally, hyaline distally, teeth lanceolate, endostome
hyaline, not adherent to exostome, basal membrane high, segments present,
perforations narrow, cilia absent. Spores
11--14 \um, smooth or papillose). Capsules mature summer (Jul--Aug.).
Rare on damp to seepy rock or soil over rock; 700--2200 m, Plagiobryoides
incrassatolimbata is characterized by large size of the habit and the unusual multistratose
border of short, wide cells. This species is similar in many respects to P.
renauldii, from which it be distinguished by its limbidium, generally
red-brown colored leaves (sometimes green), and lack of rhizoidal tubers. The sporophyte description is from H. Ochi and N. Salazar Allen
(1990). 4. Plagiobryoides limbata (Müller Hal.) J. R. Spence, Phytologia 91: 498.
2009 Bryum limbatum Müll. Hal., Syn. Musc. Frond. 2: 573. 1851 Plants in dense turfs, pale green or pink-green. Stems short, 0.5--2 cm, not julaceous, sometimes weakly
complanate, weakly branched, rhizoids sparse on proximal stem. Leaves somewhat contorted when dry,
erect to erect-spreading when wet, distant to crowded along stem, narrowly
ovate, flat or weakly concave, 0.6--1(--2) mm, not decurrent, base red;
margins plane or recurved proximally, 1-stratose, serrate distally, limbidium
strong, of (1--)2--3 layers of elongate cells, apex acute, costa not reaching
apex to very short-excurrent in smooth point, leaves of innovations smaller
with more obtuse apex and weaker costa, laminal cells somewhat heterogeneous,
distal cells irregular in shape, 20--50 x 14--20 \um, (1--)2--4:1, cells
incrassate, proximal cells rectangular, (40--)50--80 x 16--26 \um,
3--5:1, sometimes bulging, thin-walled.
Specialized asexual reproduction
absent. Sexual condition dioicous.
[Seta short, thick, red-brown,
1--2 cm, flexuose to twisted or sometimes straight. Capsule inclined to nutant, 2--3 mm, red-brown,
elongate-pyriform, hypophysis weakly to strongly differentiated,
elongate, operculum weakly convex,
conic, apiculate; peristome double, exostome pale yellow or tan proximally,
hyaline distally, teeth lanceolate, endostome hyaline to pale yellow, not
adherent to exostome, basal membrane high, segments present, perforations
narrow, cilia present, appendiculate to nodose. Spores 12--16 \um, papillose, yellow-brown.] Rare on shaded damp to seepy rock
faces along stream; 1600 m, N.C.; Mexico; West Indies; Central America; South
America. Plagiobryoides limbata is a recently collected species from 4. Plagiobryoides renauldii (Röll ex
Renauld & Cardot) J. R. Spence, Phytologia 91: 498. 2009 Bryum renauldii Röll ex
Renauld & Cardot, Bull. Soc. Roy. Bot. Belgique 38(1): 13. 1900 Plants in dense turfs, dark green to olive-green. Stems short to long, 1--3(--4) cm, not or weakly julaceous,
somewhat branched, innovations few; rhizoids sparse on proximal stem. Leaves somewhat contorted when dry,
erect when wet, distant along stem, broadly ovate to suborbicular, concave,
0.5--2(--3.5) mm, somewhat decurrent, base red-green; margins plane or
recurved proximally, 1-stratose, more or less smooth, limbidium absent, apex
broadly acute to obtuse, costa not reaching apex to rarely percurrent ,
laminal cells heterogeneous, distal cells irregular in shape, 25--50 x 16--25
\um, 1--2(--3):1, cells thin-walled,
proximal cells rectangular, (60--)80--100 x 16--24 \um, 3--5:1, bulging, thin-walled.
Specialized asexual reproduction
of large tubers on rhizoids at base of stem and in most proximal leaves, spherical,
red, (200--)300--500 \um. Sexual
condition dioicous?. Sporophytes unknown. Capsules unknown. Rare on wet soil
and soil over rock in stream; 2200 m, During a bryophyte workshop in the 6. Plagiobryoides vinosula (Cardot) J. R.
Spence, Phytologia 91: 498. 2009 Brachymenium vinosulum Cardot, Rev.
Bryol. 38: 6. 1911 Plants in dense turfs, bright green. Stems
short to moderately long, 1--2(--3) cm, not julaceous, somewhat branched,
innovations common; rhizoids sparse on proximal stem. Leaves somewhat contorted
to imbricate when dry, erect when wet, somewhat crowded along stem,
narrowly to broadly ovate, flat or weakly concave, 0.6--2(--3) mm, not
decurrent, base red; margins plane or recurved proximally, 1-stratose, more
or less smooth, limbidium absent or rarely a single indistinct layer of
elongate cells present proximally, apex acute, costa reaching apex to very short-excurrent
in smooth point, leaves of innovations smaller with more obtuse apex and
weaker costa, laminal cells somewhat heterogeneous, distal cells elongate
hexagonal, 25--60 x 16--22 \um, 1--3:1, cells thin-walled, proximal cells
long-rectangular, (60--)80--100 x 18--24 \um, 4--5:1, sometimes bulging, thin-walled. Specialized asexual reproduction by
large rhizoidal tubers on rhizoids at base of stem, spherical, red, (200--)250--400
\um. Sexual condition dioicous. Seta short, thick, red-brown, (1--)2--3
cm, flexuose to twisted. Capsule
suberect to inclined, 2--3 mm, brown, elongate-pyriform, hypophysis weakly
differentiated, short, operculum weakly convex, conic, apiculate; peristome
double, exostome pale yellow proximally, hyaline distally, teeth
lanceolate, endostome hyaline to pale
yellow, not adherent to exostome, basal membrane high, segments present,
sometimes longer than exostome, perforations narrow, cilia usually absent,
occasionally 1---2 present. Spores
18--26 \um, papillose, yellow-brown. Capsules mature June-Sept. Locally
common, damp calcareous rock at springs, including hot springs; 800--2200 m;
Ariz., Calif., Colo., N.Mex., Utah, Wyo.; Mexico. Plagiobryoides vinosula has been synonymized with P.
cellularis, but differs in its bright green elongate stems, leaves that
are somewhat contorted when dry, typically shorter distal laminal cells,
rhizoidal tubers and capsule with a short hypophysis. This latter feature also occurs in P.
cellularis, however, and more work is clearly needed to better delimit
the two species. Plagiobryoides vinosula has been found recently in |
