Microbryum

Schimper

Syn. Musc. Eur., 10. 1860,.

Etymology: Greek mikros, small, and bryon, moss
Synonyms: Phascum sect. Microbryum (Schimper) Podpera Phascum subg. Microbryum (Schimper) Limpricht Phascum sect. Pottiella (Limpricht) Paris Phascum subg. Pottiella Limpricht Pottia sect. Pottiella (Limpricht) Nyholm Pottia subg. Pottiella (Limpricht) Brotherus
Treatment appears in FNA Volume 27. Treatment on page 627. Mentioned on page 480, 587, 628, 638.

Plants in a low turf, scattered or gregarious, occasionally bulbiform, reddish-brown distally, brown proximally. Stem very short, 0.2–0.4 mm, hyalodermis absent, sclerodermis absent or weakly differentiated, central strand present or absent; axillary hairs of 3–6 cells, the proximal 1-2 cells usually with thicker walls. Leaves appressed when dry, weakly spreading, tips occasionally reflexed when moist, lanceolate, elliptical or ovate, adaxial surface weakly concave to broadly channeled, short, 0.6–1.8 mm; base not differentiated, proximal margins not differentiated; distal margins recurved at mid leaf and commonly recurved to near apex, entire or rarely serrulate near apex, margins occasionally less papillose and somewhat thicker walled than medially; apex broadly acute; costa excurrent as an apiculus, mucro or short awn, occasionally only percurrent, adaxial outgrowths occasionally present as a pad of enlarged parenchymatous cells, adaxial cells quadrate or shortrectangular or elongate, in 2 (4–6) rows; transverse-section usually round, adaxial epidermis present, adaxial stereid band absent, guide cells 2 (–4) in 1 layer, hydroid strand present, occasionally central, abaxial stereid band present, round to semicircular in sectional shape, abaxial epidermis present; proximal cells differentiated across leaf or higher medially, rectangular, 2–4: 1, walls of proximal cells usually thin; distal medial cells quadrate to hexagonal or shortrectangular, occasionally rhomboidal, small to somewhat enlarged, 11–15 µm wide, 1–2: 1, 1-stratose; papillae usually simple (seldom 2-fid), hollow, 1–6 per lumen, occasionally branching and tall, cell-walls thin to moderately and evenly thickened, convex on both sides. Specialized asexual reproduction absent. Sexual condition monoicous, usually paroicous, occasionally synoicous. Perichaetia terminal, interior leaves often somewhat enlarged, otherwise little differentiated. Seta very short-to-elongate (to 4 mm). Capsule stegocarpous or cleistocarpous, theca ovate to short elliptical, apiculate when cleistocarpous, 0.5–1.1 mm, annulus absent or of 1–2 rows of weakly vesiculose cells, persistent; operculum when differentiated low-conic, peristome teeth when present 16, irregular, often rudimentary, ligulate to triangular in shape, untwisted. Calyptra conic-cucullate, occasionally mitrate. Spores large, 20–30 µm. KOH laminal color reaction red.

Distribution

Worldwide in temperate zones

Discussion

Species 13 (4 in the flora).

Microbryum is similar to Syntrichia in its broad leaves, single stereid band, and red reaction of the lamina to KOH, but differs in the short stems, distinctive reduction series involving the sporophyte, round to semicircular costal stereid band (reniform in Syntrichia), peristomes (when present) of 16 irregular, often rudimentary, truncate peristome teeth that are large in comparison with the size of the capsule, and operculum (when present) low-conic. Adaxial costal pads of cells are occasionally present (in M. vlassovii). Distinguishing features include variation in ornamentation and size of the spores, and collections of these monoicous taxa usually include sporophytes.

Selected References

None.

Key

1 Distal laminal cells bulging very strongly medially, projecting as ôbottle-shapedö cells on the adaxial surface of the costa Microbryum vlassovii
1 Distal laminal cells weakly convex adaxially, not of distinctive shape > 2
2 Seta very short, capsules nearly spheric, cleistocarpous Microbryum floerkeanum
2 Seta elongate, capsules elliptical to cylindric, stegocarpous (occasionally operculum not dehiscent) or rarely cleistocarpous > 3
3 Spores smooth or tuberculate (seldom also weakly papillose), 22-30 µm Microbryum starckeanum
3 Spores papillose or spiculose, 28-39 µm Microbryum davallianum
... more about "Microbryum"
elongate +, shortrectangular +  and quadrate +
weakly concave +  and broadly channeled +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
of 1;2 rows +
of 1-2 rows +  and differentiated +
long-excurrent +  and short-excurrent +
Richard H. Zander +
Schimper +
round +  and semicircular +
papillose +  and smooth +
usually slightly wider +
usually ovate;oblong +
not differentiated +
obovoid +
mitrate +  and conic-cucullate +
cleistocarpous +  and stegocarpous +
synoicous +, paroicous +, monoicous +, sexual +  and asexual +
vesiculose +  and parenchymatous +
3 (?) +  and 6 (?) +
elongate-rhomboid +  and elongate +
enlarged +
tomentose +  and bare +
percurrent +  and excurrent +
serrulate +  and entire +
rhomboidal;shortrectangular;quadrate;hexagonal +
enlarged +  and small to somewhat +
Worldwide in temperate zones +
differentiated +
Greek mikros, small, and bryon, moss +
multicellular +
yellow +  and orange-red or red +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
concave;keeled;channeled;ovoid;lanceolate or lingulate +
spathulate +  and ovate +
reduced +
occasionally less papillose and somewhat thicker walled +
dentate +  and entire +
papillose +
photosynthetic +
branching +, hollow +  and simple +
1 +  and 6 +
flattened +  and 2-fid +
lateral +  and terminal +
lateral +  and terminal +
red +, orange +  and yellow +
1 (?) +  and 2 (?) +
not differentiated +
Syn. Musc. Eur., +
straight +
elongate +
short;elongate +
2 +  and 1 +
red +  and laminal +
rounded-triangular +  and rounded-pentagonal +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
Phascum sect. Microbryum +, Phascum subg. Microbryum +, Phascum sect. Pottiella +, Phascum subg. Pottiella +, Pottia sect. Pottiella +  and Pottia subg. Pottiella +
Microbryum +
Pottiaceae subfam. Pottioideae +
ovate;short elliptical +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
ovate +, elliptical +  and lanceolate +
yellow distally and red +, orange +, red +  and yellow +
rectangular +
stemless +  and perigoniate +
brown;reddish-brown +
plant +  and gregarious +
occasionally smaller than the perichaetiate +