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pseudoleskea moss

Habit Plants medium-sized to large, in thick mats, green, yellow-green, or orange-green. Plants in mats or patches, green, golden green, brown-green, or blackish, rarely with orange or red tinge.
Stem(s)

with branches robust, julaceous, apices usually curving up;

central strand present;

paraphyllia many, filamentous to foliose, branched.

and branch leaves usually similar, rarely differentiated.;

stem leaves appressed to erect when dry, erect to erect-spreading or rarely squarrose when moist, ovate, ovate-lanceolate, or oblong, symmetric or sometimes asymmetric, not to distinctly plicate on either side of costa;

margins plane to recurved, entire to serrate distally, limbidium absent or rarely present;

apex broadly rounded, acute, or acuminate; ecostate to costa percurrent, sometimes 2-fid, occasionally sinuate distally;

alar cells shorter than laminal cells, isodiametric to transversely elongate, region usually distinct;

laminal cells isodiametric to elongate-rhomboidal or linear-fusiform, often prosenchymatous, sometimes obscure or opaque, smooth, papillose over lumen, or prorulose distally, walls thin to usually firm or thick, rarely pitted.

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.

Branch leaves

often smaller;

apex sometimes less acute;

costa weaker.

Seta

elongate, thin, straight or somewhat curved, often twisted.

Sexual condition

dioicous or autoicous;

perigonia budlike, on primary stems;

perichaetial leaves on primary stems or rarely secondary branches, differentiated, opaque to translucent, apex longer, more acuminate than stem and branch leaves, costa short to excurrent.

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.

erect to horizontal, long-exserted, oblong to pyriform, symmetric to asymmetric-curved, smooth;

stomata absent or present, phaneropore;

annulus absent or present;

operculum conic, short- to long-rostrate;

peristome double, perfect to variously reduced;

exostome teeth lanceolate or linear-lanceolate, lamellae present, sometimes faint or absent, striolate to densely papillose;

endostome basal membrane low to high, free or sometimes adherent to exostome at base, segments broad and keeled to linear, sometimes absent, cilia well developed to rudimentary or absent.

Calyptra

usually cucullate, small, fugacious, usually smooth.

Spores

16–22 µm.

smooth to variously roughened.

Specialized

asexual reproduction rarely present, of clustered flagelliform branchlets in axils of distal branch leaves.

Pseudoleskea radicosa

Leskeaceae

Distribution
North America; Eurasia; Atlantic Islands (Iceland)
[WildflowerSearch map]
Nearly worldwide except Antarctica
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.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera ca. 18, species ca. 80 (9 genera, 28 species in the flora).

Leskeaceae is a heterogeneous family, with genera exhibiting widely divergent morphologies, and with some taxa more closely related to Anomodontaceae, Pterigynandraceae, and Thuidiaceae (J. R. Spence 1996). Recent molecular studies confirm this phylogenetic heterogeneity (A. M. Gardiner et al. 2005; M. S. Ignatov et al. 2006; D. García-Avila et al. 2009), and suggest that there are at least three distinct groups of core genera, centered around Lescuraea, Leskea, and Pseudoleskeella, respectively. Although there is some merit in recognizing Pseudoleskeaceae, following W. P. Schimper, for Lescuraea, Pseudoleskea, Ptychodium, and Rigodiadelphus, this does not solve the problem of where to place Pseudoleskeella. Morphological and molecular evidence also suggests that Claopodium is near Anomodon, and Leptopterigynandrum near Heterocladium. On the other hand, core Leskeaceae, including Haplocladium, Leskea, and Lindbergia, are phylogenetically closer to Thuidiaceae than to the Pseudoleskeaceae group. A. Vanderpoorten et al. (2003b) have shown that Platylomella, currently in Amblystegiaceae, may be close to the Leskeaceae-Thuidiaceae clade, although its correct placement remains unresolved. The original concepts of Leskeaceae and Thuidiaceae, based on sporophyte characters (W. R. Buck and H. A. Crum 1990), are not supported by either gametophyte morphology or molecular data (Spence; Gardiner et al.).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Plants large; stem apices hooked; branches few or absent; leaves 1.6-2.3 mm, strongly falcate-secund, pluriplicate; apices long-acuminate.
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.
var. radicosa
2. Plants small; leaves strongly concave, often incurved, 0.8-1.3 mm; apices acute to short-acuminate; medial laminal cells pellucid.
var. compacta
1. Stems with paraphyllia present or rarely absent
→ 2
1. Stems with paraphyllia absent
→ 7
2. Leaf hair-points or long-acuminate apices usually present; limbidium sometimes present; costae pellucid; medial laminal cells finely and obscurely 1- or multipapillose over lumen.
Claopodium
2. Leaf hair-points or long-acuminate apices absent; limbidium absent; costae opaque; medial laminal cells papillose over lumen, prorulose, or smooth
→ 3
3. Stem and branch leaves dimorphic; stems ± pinnate; paraphyllia cells papillose.
Haplocladium
3. Stem and branch leaves similar; stems irregularly branched or unbranched; paraphyllia cells smooth or prorulose
→ 4
4. Medial laminal cells prorulose or smooth
→ 5
4. Medial laminal cells distinctly papillose over lumen
→ 6
5. Medial laminal cells more than 4:1, walls thin; proximal cells more than 3:1; capsules erect, symmetric.
Lescuraea
5. Medial laminal cells 2-3:1, walls firm to thick; proximal cells usually 1-2:1; capsules inclined, asymmetric.
Pseudoleskea
6. Leaves oblong-ovate or ovate-lanceolate; apices acute, acuminate, or obtuse; apical cells ± quadrate except at very tip; paraphyllia few; sexual condition autoicous; capsules erect; peristome reduced; on bark of trees, occasionally rock, lower elevations.
Leskea
6. Leaves ovate-lanceolate; apices acuminate; apical cells elongate; paraphyllia usually many; sexual condition dioicous; capsules inclined; peristome well developed; on soil or rock, montane.
Pseudoleskea
7. Costae strong, single, more than 1/2 leaf length; leaves wide-spreading to squarrose when moist; medial laminal cells 1-papillose over lumen.
Lindbergia
7. Costae strong and single to weak, short, single or double; leaves erect-spreading when moist; medial laminal cells prorulose, smooth, or papillose
→ 8
8. Leaf hair -points present; proximal laminal cells 3-4:1, walls pitted.
Pseudoleskea
8. Leaf hair-points absent; proximal laminal cells 1-2:1, walls not or obscurely pitted
→ 9
9. Costae less than 1/2 leaf length, not obscure distally, sometimes double, rarely nearly ecostate
→ 10
9. Costae more than 1/2 leaf length to percurrent, often obscure distally, single
→ 11
10. Leaves strongly appressed; medial laminal cells papillose.
Leptopterigynandrum
10. Leaves catenulate; medial laminal cells smooth.
Pseudoleskeella
11. Leaves not to weakly plicate; branches erect, clustered; brood branchlets present; medial laminal cells mixed isodiametric, to 2:1; capsules erect to inclined, symmetric; peristome reduced.
Leskeella
11. Leaves plicate; branches not erect or clustered; brood branchlets absent; medial laminal cells usually elongate, (2-)3:1; capsules inclined, asymmetric; peristome well developed.
Pseudoleskeella
Source FNA vol. 28, p. 359. FNA vol. 28, p. 340. Author: John R. Spence.
Parent taxa Leskeaceae > Pseudoleskea
Sibling taxa
P. atricha, P. baileyi, P. incurvata, P. patens, P. saviana, P. stenophylla, P. tribulosa
Subordinate taxa
P. radicosa var. compacta, P. radicosa var. denudata, P. radicosa var. radicosa
Claopodium, Haplocladium, Leptopterigynandrum, Lescuraea, Leskea, Leskeella, Lindbergia, Pseudoleskea, Pseudoleskeella
Synonyms Hypnum radicosum, Lescuraea radicosa
Name authority (Mitten) Macoun & Kindberg: Cat. Canad. Pl., Musci, 181. (1892) Schimper
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