Ptychostomum arcticum

(R. Brown) J. R. Spence

Phytologia 87: 20. 2005.

Illustrated
Basionym: Pohlia arctica R. Brown Chlor. Melvill., 38. 1823
Synonyms: Bryum arcticum (R. Brown) Bruch & Schimper B. bryoides (R. Brown) Ångstrom B. purpurascens (R. Brown) Bruch & Schimper Ptychostomum bryoides (R. Brown) J. R. Spence P. purpurascens (R. Brown) J. R. Spence
Treatment appears in FNA Volume 28. Treatment on page 168. Mentioned on page 167, 169.

Plants in dense or open turfs, red, pink, green, or yellow-green. Stems 0.5–3 cm, fertile stems comose, innovations evenly foliate. Leaves shiny yellow-green to red or pink, crowded, strongly contorted to shrunken when dry, ovatelanceolate, flat, 0.5–3 mm, often gradually enlarged toward stem apex; base usually green, not decurrent; margins revolute proximally, limbidium strong, in 2 or 3 rows; apex acute to acuminate; costa excurrent to long-excurrent, awn smooth or denticulate; proximal laminal cells long-rectangular, 3–5: 1; medial and distal cells 15–25 µm wide, 2–3: 1, walls thin to moderately thick. Specialized asexual reproduction absent. Sexual condition polyoicous, variable, often populations either synoicous or only archegoniate. Seta brown or redbrown, 1–3 cm, slender, straight to somewhat flexuose. Capsule brown, shape highly variable, elongate-pyriform to clavate, symmetric to somewhat curved, 3–5 mm, mouth orangebrown to red; hypophysis slender; operculum short-conic, weakly apiculate; peristome variable, reduced; exostome teeth yellow or brown, hyaline distally, lamellae straight, sometimes with small pores near base along mid line; endostome weakly adherent to exostome, basal membrane low to 1/2 exostome height, segments with slitlike perforations, cilia absent or rudimentary. Spores with size often variable in same capsule, 24–30 (–32) µm, yellow.


Phenology: Capsules mature Jul–Aug.
Habitat: Moist soil banks, wet soil
Elevation: low to high elevations (0-4500 m)

Distribution

V28 267-distribution-map.gif

Greenland, Alta., B.C., Man., Nfld. and Labr., Que., Alaska, Calif., Mont., Nev., Oreg., Wash., Wyo., Eurasia

Discussion

Ptychostomum arcticum is one of the most variable and confusing species in the genus. Much of this variation has been described as a series of very closely related species, including P. bryoides and P. purpurascens, differing in minor details of the leaves and capsule. D. T. Holyoak (2004) synonymized several of these segregates with P. arcticum, which is here tentatively accepted. The segregates that have been reported from the flora area are distinguished below based on the work of E. Nyholm (1986+, fasc. 3). Their distribution and ecology remain poorly understood, but P. purpurascens is reported from arctic North America, while P. bryoides is reported from Greenland. Capsules are needed for identification.

Ptychostomum purpurascens is immediately distinguished by the distal laminal cells 22–35 µm wide, capsules elongate-pyriform and symmetric, exothecial cells transversely rectangular, in 2–4 rows, and exostome teeth with small holes present along the mid line at base. Ptychostomum arcticum and P. bryoides contrast by distal laminal cells 17–24 µm wide; capsules clavate to ovate, symmetric or curved, exothecial cells quadrate, in 2–6 rows, and exostome teeth lacking small holes.

Selected References

None.

Lower Taxa

None.

"narrower" is not a number."narrow" is not a number.

... more about "Ptychostomum arcticum"
acute;acuminate +
John R. Spence +
(R. Brown) J. R. Spence +
denticulate +
reduced +
curved +  and straight +
not decurrent +
Pohlia arctica +
cucullate +
0.6 cm6 mm <br />0.006 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
nutant +, inclined +  and suberect +
long-exserted +
elongate-pyriform +  and clavate +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
not inflated +
not differentiated +
appendiculate +
rudimentary +
excurrent +  and long-excurrent +
subpercurrent +
short-rhomboidal +
Greenland +, Alta. +, B.C. +, Man. +, Nfld. and Labr. +, Que. +, Alaska +, Calif. +, Mont. +, Nev. +, Oreg. +, Wash. +, Wyo. +  and Eurasia +
low to high elevations (0-4500 m) +
hyaline;pale-yellow +
hyaline +, brown +, orange +  and yellow +
hyaline +, brown +  and yellow +
Moist soil banks, wet soil +
not +  and differentiated +
narrowly ovatelanceolate;triangular +
polyoicous +, monoicous +, dioicous +  and sexual +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
yellow-green +  and red or pink +
erect;erect-spreading +
ovatelanceolate +
enlarged +  and shrunken +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
2-stratose +  and 1-stratose +
revolute entire +  and denticulate +
1 (?) +, 2 (?) +  and 3 (?) +
rhomboidal +  and hexagonal +
orangebrown +  and red +
short-rectangular +  and quadrate +
short-conic +
lateral +  and terminal +
lateral +  and terminal +
diplolepidous-alternate +
Capsules mature Jul–Aug. +
differentiated +
smooth;papillose +
redbrown +  and brown +
flexuose +  and straight to somewhat +
elongate +
slender +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Illustrated +
germinating +
variable +
branching +  and foliate +
4 cm40 mm <br />0.04 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Bryum arcticum +, B. bryoides +, B. purpurascens +, Ptychostomum bryoides +  and P. purpurascens +
Ptychostomum arcticum +
Ptychostomum subg. Ptychostomum +
species +
lanceolate +
distinct +
archegoniate +
straight +
specialized +
synoicous +, polyoicous +, sexual +  and asexual +
sinuate +
incrassate +
thin;moderately thick +
yellow-green +, green +, pink +  and red +
large;small to very +