Pseudoleskea radicosa

Plants medium-sized to large, in thick mats, green, yellow-green, or orange-green. Stems with branches robust, julaceous, apices usually curving up; central strand present; paraphyllia many, filamentous to foliose, branched. Leaves appressed to somewhat erect when dry, erect-spreading when moist, glossy or dull, ovate to ovate-lanceolate, asymmetric, usually falcate to falcate-secund, 0.6–2(–2.4) mm; margins narrowly recurved to mid leaf or to near acumen; apex abruptly acute to short- or long-acuminate, hair-point absent; costa subpercurrent to percurrent, yellow-green, sometimes sinuate; alar cells transversely elongate to quadrate, region small to medium-sized; medial laminal cells homogeneous, short-rhomboidal, elliptic, or fusiform, to 40 µm, 2–3(–4):1, pellucid to opaque, prorate to near base, lumina larger than 10 µm, walls thin or rarely firm, not pitted; apical cells 2–3:1; juxtacostal cells somewhat shorter than more distal cells, walls not pitted. Capsule erect to suberect, symmetric, 1–2 mm; endostome basal membrane 1/4–1/3 exostome length, segments shorter than exostome, cilia usually present, 1 or 2, sometimes reduced. Spores 16–22 µm.

Distribution

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North America, Eurasia, Atlantic Islands (Iceland).

Discussion

Varieties 3 (3 in the flora).

Pseudoleskea radicosa is a common and variable species found at moderate to high elevations; the capsules mature in summer. Two of the three varieties are quite distinctive. Pseudoleskea radicosa is closely related to P. incurvata but differs in the longer, more homogeneous, thin-walled, and wider laminal cells. Combined ecological, molecular and morphological studies of the varieties are needed to determine their distinctiveness.

Selected References

None.

Lower Taxa

Pseudoleskea radicosa var. compacta, Pseudoleskea radicosa var. denudata, Pseudoleskea radicosa var. radicosa

Key

1	Plants large; stem apices hooked; branches few or absent; leaves 1.6-2.3 mm, strongly falcate-secund, pluriplicate; apices long-acuminate.	Pseudoleskea radicosa var. denudata
1	Plants small to medium-sized; stem apices not distinctly hooked; branches many; leaves usually less than 1.6 mm, straight, falcate, or falcate-secund, 2-plicate; apices predominantly short-acuminate to acute	> 2
2	Plants medium-sized; leaves weakly to moderately concave, not incurved, 1.2-1.7 mm; apices usually long-acuminate; medial laminal cells opaque.	Pseudoleskea radicosa var. radicosa
2	Plants small; leaves strongly concave, often incurved, 0.8-1.3 mm; apices acute to short-acuminate; medial laminal cells pellucid.	Pseudoleskea radicosa var. compacta