Andreaeobryum macrosporum

Steere & B. M. Murray

Phytologia 33: 407. 1976,.

Treatment appears in FNA Volume 27. Treatment on page 109.

Protonemata massive, globose, multicellular, giving rise to a branched and thallose protonema, and protonematal appendages that persistent, cylindrical and multiseriate, to 2 mm. Stems 2–4 (–6) cm, hyalodermis absent, sclerodermis of 3–4 thicker-walled cells, central strand absent, sparse, redbrown, 1-seriate rhizoids at base. Leaves little changed on drying, erect-spreading, falcate-secund when moist, near stem base 0.3–0.4 mm, gradually larger toward stem apices, to 1–1.7 mm, clustered in the stem apices as a fistlike coma, base scarcely differentiated to ovate or elliptic, somewhat decurrent, lamina gradually to abruptly ending in the subula in the distal 1/5 or less, lamina plane to gently concave, margins plane to slightly incurved proximally, smooth to weakly sinuose in the subula; basal-cells gradually differentiated, occasionally hyaline near insertion, short-rectangular, 2 (–3):1, all cells distal to the base roundedquadrate, occasionally slightly oblate, 12–20 (–25) µm, all cells firm, thick-walled, more thickened at the cell angles, thickenings not irregular, not trigonous, cell-walls smooth, convex to bulging-mammillose, especially in the subula. Sexual condition dioicous; perigonia gemmate, terminal and lateral, perigonial leaves broadly ovate, short apiculate, interior perigonial leaves 1-stratose, ecostate, wider than long, antheridia usually 4–6, on 2-seriate stalks; perichaetia terminal or lateral, 1–4 per stem, interior leaves little different from the cauline, minute, multistratose, innermost leaf little longer than the archegonium. Seta redbrown, concolorous with capsule base, massive, not twisted, 0.6–1.2 (–2) × 0.2–0.4 mm, foot long-tapering, not swollen. Capsule redbrown to shining black with age, the broad base paler and the narrower, conic distal portion darker and developing 4–8 hygroscopic, longitudinal, dehiscent slits for spore dispersal.


Phenology: Capsules mature late summer.
Habitat: Calcareous rock in Arctic and subarctic areas
Elevation: low to high elevations

Distribution

V27 124-distribution-map.gif

B.C., N.W.T., Yukon, Alaska.

Discussion

Andreaeobryum macrosporum is rare or occasional within its range, though locally abundant. Didymodon subandreaeoides (Pottiaceae), also of limestone substrates and found in the same areas, likewise has dimorphic leaves that are cochleariform on fragile branchlets or portions of some stems; it has a stem central strand. Both that species and the similar D. nigrescens have 1-stratose leaves.

Selected References

None.

Lower Taxa

None.

"um" is not declared as a valid unit of measurement for this property."um" is not declared as a valid unit of measurement for this property."broadest" is not a number.

... more about "Andreaeobryum macrosporum"
Patricia M. Eckel +
Steere & B. M. Murray +
short-rectangular +
differentiated +
roundedquadrate +
differentiated +
narrower +  and broad +
thick-walled +  and thicker-walled +
brown;hyaline +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
redbrown;shining black +
angular-ovate +  and rounded +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
bulging-mammillose +
dioicous +  and sexual +
fist-like +
differentiated +
B.C. +, N.W.T. +, Yukon +  and Alaska. +
low to high elevations +
not swollen +  and long-tapering +
Calcareous rock in Arctic and subarctic areas +
plane +  and gently concave +
falcate-secund +
squamiform +  and ovatelanceolate +
larger +
0.1 cm1 mm <br />0.001 m <br /> (0.17 cm1.7 mm <br />0.0017 m <br />) +
smooth;weakly sinuose +
lateral +  and terminal +
Capsules mature late summer. +
0 cm0 mm <br />0 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
not twisted +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
concolorous +  and redbrown +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
massive +
0.2mm;0.4mm +
flagelliform +
spheric;ovoid +
not developed +
elongate +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
multistratose +
mammillose +
Andreaeobryum macrosporum +
Andreaeobryum +
species +
not trigonous +
longitudinal +  and transverse +
clear green;olive green +
plant +  and mat-forming +