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BFNA Title: Pseudoleskea |
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XX. PSEUDOLESKEA Bruch & Schimper, Bryol. Eur. 5: 147
(fasc. 49--51. Monogr. 1). 1852 * (Latin pseudo, false and Leskea) John R. Spence Plants prostrate, in thin to thick mats,
green, yellow-green, orange-green or gold-green, becoming brown with age. Stems slender to robust, not fragile,
tips often ascending or hooked, irregularly branched, secondary branches
appressed to ascending or erect, not flagelliform at tips, sometimes
julaceous, older primary stems becoming stoloniferous; paraphyllia common,
filamentous to foliose, not much branched, cells smooth or prorulose,
becoming scarce on older stems; rhizoids in clusters arising from base of
stem leaves. Leaves of stems and
branches similar although branch leaves smaller, ovate to ovate-lanceolate,
weakly to strongly concave, more or less symmetric, appressed to julaceous when
dry, not catenulate, erect-spreading when wet, dull to lustrous, with or
without distinct hair-point; lamina weakly to strongly plicate on either side
of costa, abruptly acute to long-acuminate, margins smooth to serrulate
distally, recurved proximally; costa moderately strong, 2/3 length of lamina
to subpercurrent, green to yellow-green, not or weakly sinuose; mid-laminal
cells quadrate to elongate-rhomboidal, 1--4(--5):1 firm walled to thin-walled, 1-papillose to prorate,
laminal cells in acumen similar to more proximal cells, strongly prorate,
translucent or opaque due to dense chloroplasts; alar cells distinct in small
to large groups, transversely elongate, quadrate to short-rectangular,
smooth, juxtacostal cells similar to median cells but mostly shorter, walls
pitted or not. Specialized asexual reproduction
absent. Sexual condition
dioicous; perichaetial leaves pale translucent, longer and more acuminate
than the cauline, erect when wet, costa percurrent. Capsule red to red-brown, ovate to cylindric, inclined to erect,
asymmetric or rarely nearly symmetric, operculum conic, rarely with small
apiculus; annulus lacking; peristome double, well developed, exostome teeth
lanceolate, striate to papillose, bordered, endostome of high basal membrane,
segments slender lanceolate to filiform, keeled, cilia 1--3, well developed
to short and rudimentary. Calyptra cucullate.
Spores small, papillose. Species ca. 12
(8 in the flora): Northern Hemisphere, mostly montane to alpine regions. Pseudoleskea is a group of Northern Hemisphere
species found on rock and soil, typically in cool to cold climates. Southern
Hemisphere species of Pseudoleskea
are not closely related to those of the Northern, with numerous morphological
differences, and are probably closest to Lindbergia,
according to recent molecular studies (M. S. Ignatov et al. 2007). Pseudoleskea
differs from Lescuraea in the
shorter and mostly thicker-walled laminal cells and in the mostly perfect
hypnoid peristome, showing some reduction in a few species. J. R. Rohrer
(1986) presented a useful comparison of differences between the genera. Pseudoleskea baileyi
does not belong in the genus and appears to be closest morphologically to the
East Asian Rigodiadelphus (M. U. Krieger, unpublished); it is included here for completeness. SELCTED REFERENCES: 1. Median
laminal cells isodiametric to elongate, papillose over the lumen. 2.
Leaves with long slender acuminate apex, median laminal cells elongate, 2--4:1,
most papillae off-centered on distal cell lumens; bark and twigs of shrubs
and trees ..........…… 7. Pseudoleskea stenophylla 2.
Leaves ovate, short-acuminate to acute, median laminal cells short,
predominantly isodiametric, papillae mostly centered over lumens, soil or
rock, never corticolous. 3.
Stems and branches mostly julaceous to appressed, leaves large, typically more
than 0.8 mm, margins recurved proximally, lamina cells opaque, papillae low
to large, but not distinctly pointed-mammillose, costa ending in short
projection, never morningstar-like .....................................................................
4. Pseudoleskea patens 3.
Stems and branches mostly catenulate, leaves small, typically less than 0.8
mm, margins plane, lamina cells translucent, papillae large, distinctly
pointed-mammillose, costa ending in strong morningstar-like
extension of apical abaxial cells ........ 8. Pseudoleskea tribulosa 1. Median
laminal cells mostly rhomboidal, 2--4:1, smooth to prorate over distal cell ends. 4.
Leaves with distinct hair-point, paraphyllia absent, costa weak, reaching 2/3\x
leaf length, stem lacking central strand ...........
2. Pseudoleskea baileyi 4.
Leaves lacking hair-point, paraphyllia present although sometimes scarce,
costa mostly percurrent, stem with central strand of small cells. 5.
Lamina cells of stem leaves, except alar, distinctly and strongly pitted ..........................
1. Pseudoleskea atricha 5.
Lamina cells of stem leaves not pitted or weakly pitted only near leaf base. 6.
Proximal laminal cells elongate rhomboidal, 3:1 or more, longer than more
distal cells, median lamina cells strongly prorate, distal leaf margins
strongly and broadly recurved, leaves long-acuminate
.................................. 6. Pseudoleskea saviana 6.
Proximal lamina cells quadrate to short-rectangular, 1--2:1, same length or
shorter than distal cells, median lamina cells obscurely prorate to nearly
smooth, distal leaf margins weakly recurved, leaves acute to short-acuminate. 7.
Cells of distal leaf margins short, mostly less than 2:1, median-distal
laminal cells mostly less than 8 \um wide, incrassate, often very
heterogeneous in shape, alar cells mostly quadrate, paraphylla
not branched ............................. 4. Pseudoleskea incurvata 7.
Cells of distal leaf margin elongate, more than 2:1, median-distal laminal
cells mostly more than 10 \um wide, thin-walled, mostly homogeneous, alar
cells often longer than wide, paraphyllia often branched
............................. 5. Pseudoleskea radicosa 1. Pseudoleskea
atricha (Kindberg in J. Macoun) Kindberg, Ottawa Nat. 7: 20. 1893 Pseudoleskea
atrovirens var. atricha Kindberg in J. Macoun, Cat. Canad. Pl., Musci, 180. 1892; Lescuraea atricha
(Kindberg) Plants robust, in thick, stiff mats, green,
yellow-green, orange-green or black-green, becoming brown with age. Stems prostrate, with central strand,
branches robust, often julaceous, mostly prostrate, paraphyllia common,
predominantly filamentous, not branched. Leaves
ovate, asymmetric, appressed to julaceous when dry, erect spreading when wet,
rarely somewhat falcate, dull, lacking hair-point, (0.5--)1--1.2 mm;
gradually acute to rarely short acuminate, margins recurved proximally, costa
percurrent, green to yellow-green, somewhat sinuose; median laminal cells
opaque, elongate-rhomboidal, 3--4:1, mostly less than 40 \um, incrassate,
distinctly prorate, strongly pitted, laminal cells in acumen similar to proximal
cells, alar cells distinct in medium-sized groups, transversely elongate,
quadrate to short-rectangular, smooth, juxtacostal cells similar to median
cells but mostly shorter, walls pitted or not. Capsule cylindric, inclined to suberect, asymmetric, 0.5--1.2 mm,
operculum smooth conic; basal membrane 1/3--1/2\x length of exostome,
segments shorter than exostome, cilia well developed to occasionally
rudimentary. Spores (10--)12--18(--20) \um. Capsules
mature summer (Jul--Aug). Local and uncommon on subalpine and alpine rock
outcrops or rarely on mineral soil, 600--2300 m; B.C.; A local high
elevation endemic, Pseudoleskea atricha is
characterized by plants with ovate leaves having an acute but not acuminate
apex, and incrassate laminal cells that are strongly pitted. Only P. baileyi also
has strongly pitted cells, but it differs in leaves with long acumen and hair-point,
and stems lacking paraphyllia. 2. Pseudoleskea
baileyi Best
& Grout, N. Amer. Musc. Pl., 474. 1917 Lescuraea baileyi (Best & Grout) Plants robust, in thick stiff mats, green,
yellow-green, becoming orange-green, orange-brown to brown with age. Stems prostrate, lacking central
strand, branches slender to robust, often julaceous, mostly prostrate but
with upcurved tips, paraphyllia absent. Leaves ovate-lanceolate, mostly
symmetric, appressed when dry, erect spreading when wet, strongly
falcate-secund, dull, 1.5--2.5 mm, acumen ending in a short to long more or
less hyaline hair-point, margins recurved proximally, costa ending in acumen,
not percurrent, green to yellow-green, not usually sinuose; median laminal
cells translucent, elongate-rhomboidal, 2--3:1, mostly less than 30 \um,
incrassate, prorate, often somewhat pitted, laminal cells in acumen similar
to proximal cells, alar cells distinct in medium-sized groups, quadrate to
short-rectangular, smooth, juxtacostal cells similar to median cells but
longer and narrower, to 60 \um, walls usually pitted. Capsule broadly cylindric, erect to suberect, symmetric, 0.8--1.7
mm, operculum conic-apiculate; basal membrane 1/3--1/2 length of exostome,
endostome segments often longer than exostome teeth, cilia slender, 1--2 or
often rudimentary to absent. Spores
(14--)20--28 \um. Capsules mature spring--summer (May--Jul). Locally common on bark of branches and twigs of trees and shrubs at moderately high elevations, descending to near sea level in northern portion of range, occasional on rock, rarely soil; 85--1400 m; B.C.; Alaska, Oreg., Wash. Pseudoleskea
baileyi
is a distinctive endemic species, extending into the 3. Pseudoleskea
incurvata
(Hedwig) Loeske, Hedwigia
50: 313. 1911 Leskea incurvata
Hedwig, Sp. Musc. Frond., 216, plate 53, figs. 8--14. 1801; Lescuraea incurvata
(Hedwig) Plants medium to large, in thick mats, green
or yellow-green, orange-green or rarely black-green, becoming brown with age.
Stems prostrate, with central
strand, branches robust, often julaceous, apices mostly turned up,
paraphyllia common, filamentous to foliose, branched. Leaves ovate to ovate-lanceolate, asymmetric, appressed to
somewhat erect when dry, mostly falcate to falcate-secund, erect spreading
when wet, glossy or dull, lacking hair-point, 0.8--2(--2.5) mm; gradually to
abruptly acute to short or rarely long-acuminate into a short to moderately
long acumen, margins strongly and narrowly recurved to near acumen, costa
sub-percurrent to percurrent, orange-green, sometimes sinuose; median laminal
cells mostly opaque, heterogeneous, mixed isodiametric to short-rhomboidal or
elliptic, rarely fusiform, 1--2(--3):1, mostly less than 25 \um, firm-walled
to strongly incrassate with narrow lumens usually less than 8 \um, pellucid
to opaque, prorate to near base, not pitted, laminal cells in acumen similar
to proximal cells but shorter, mostly 1--2:1, alar cells distinct in large
groups, transversely elongate to quadrate, smooth, juxtacostal cells similar
to median cells but somewhat shorter than cells above, walls not pitted. Capsule cylindric, erect to suberect,
symmetric, 1--2.5 mm, operculum smooth, conic; basal membrane low, 1/4 to 1/3
length of exostome, segments shorter than exostome, cilia present, 1--2. Spores 10--20 \um. Pseudoleskea
incurvata
is a complex and highly variable species. Most plants can be told from P. radicosa
by the variably shaped thick-walled median laminal and proximal cells that
are overall mostly short, and by the relatively short cells in the
acumen. Three varieties are recognized
here. Although there are intermediate specimens, the three varieties are
often quite distinct. Combined ecological, molecular and morphological
studies of the varieties are needed to determine their distinctiveness. 1. Plants
large, leaves 1.5--2.5 mm, distinctly falcate-secund, long-acuminate, laminal
cell prorae indistinct ………………………3a. Pseudoleskea invurvata
var. gigantea 1. Plants
small to medium, leaves mostly less than 1.5 mm, straight, falcate or
falcate-secund, predominantly short acuminate to acute, laminal cell prorae distinct. 2. Leaves 1--1.5 mm, short to sometimes moderately long-acuminate, median
laminal cells elliptic with rounded corners, mostly longer than wide ……………………………………..3b.
Pseudoleskea incurvata
var. incurvata 2. Leaves smaller, mostly 0.8--1.1 mm, acute to short-acuminate, median laminal cells predominantly isodiametric and angular …………………3c. Pseudoleskea invurvata var. tenuiretis 3a. Pseudoleskea
incurvata var. gigantea ( Lescuraea incurvata
var. gigantea Plants large. Stems long, with branches few or none. Leaves 1.5--2.5 mm, distinctly falcate-secund, long-acuminate,
acumen as long or longer than rest of leaf, laminal
cell prorae indistinct. Capsules rare, mature summer (June-Aug). Uncommon to
locally common on mineral soil and soil over boulders and outcrops, 600--2100
m; B.C.; The var. gigantea
is endemic to western 3b. Pseudoleskea
incurvata var. incurvata Plants medium-sized. Stems long, with branches few to common, sometimes julaceous. Leaves 1--1.4(--1.5) mm, falcate to
falcate-secund, abruptly acute to short to modernately
acuminate, acumen shorter than rest of leaf, median laminal cells elliptic
with rounded corners, mostly longer than wide, prorae
distinct. Capsules mature summer (June-August). Locally common on dry siliceous boulders, rare on calcareous rock and mineral soil, often along streams; 900--3300 m; Greenland; Alta., B.C., Nfld. & Labr., N.W.T., ; Alaska, Calif., Colo., Idaho, Mich., Mont., Nev., N.H., Oreg., Utah, Wash.; Eurasia. 3c. Pseudoleskea
incurvata var. tenuiretis (Culmann) Podpĕra, Consp. Musc. Eur.,
531. 1954 Pseudoleskea
filamentosa var. tenuiretis Culmann, Rev. Bryol. 37: 94. 1910 Plants small, compact. Stems relatively short, with numerous julaceous side branches. Leaves 0.8--1(--1.1) mm, not falcate-secund, ovate with abruptly acute to short-acuminate apex, acumen short, median laminal cells predominantly isodiametric and angular, prorae distinct. Capsules rare, mature summer (June-August). Uncommon on dry calcareous to rarely siliceous boulders and outcrops, rarely on exposed mineral soil; 1400--2400 m; Alta., B.C.; Calif., Mont., Utah; w Eurasia. 4. Pseudoleskea
patens (Lindberg) Kindberg, Canad. Rec. Sc. 6:
20. 1894 Lescuraea patens Lindberg, Meddeland.
Soc. Fauna Fl. Fenn. 14: 75. 1888; Lescuraea patens (Lindberg) Arnell & C. Jensen Plants small to medium, in slender mats, dark
green or olive-green to black-green, rarely yellow-green, becoming brown with
age. Stems prostrate, with central
strand, branches slender to robust, often julaceous, mostly prostrate, tips sometimes
curved up, paraphyllia common, filamentous to foliose, not branched. Leaves ovate, asymmetric, appressed
to julaceous when dry, erect-spreading to patent when wet, not or rarely
falcate, dull, lacking hair-point, (0.6--)0.7--1 mm; abruptly acute to rarely
short-acuminate, margins recurved proximally; costa not reaching acumen,
green to orange-green, somewhat sinuose, abaxial cells at tip not or only weakly projecting, not
morning-star like; median laminal cells opaque, predominantly quadrate 1(--2):1,
mostly less than 18 \um, incrassate, moderately to strongly low rounded
papillose over lumen or sometimes papillae off-centered; laminal cell walls
not pitted, cells in acumen similar to proximal cells, alar cells distinct in
large groups, quadrate to transversely elongate, proximal juxtacostal cells
similar to median cells but mostly shorter, walls pitted or not. Capsule curved, inclined, asymmetric,
0.5--2 mm, operculum smooth conic; basal membrane 1/3--1/2 length of
exostome, segments shorter than exostome, cilia well developed. Spores 10--14 \um. Capsules mature in summer, July-Aug. Common on shaded to exposed rocks and outcrops, rarely on mineral soil, often near streams; mostly 900--3500 m; Alta., B.C., Nfld. & Labr., N.S., N.W.T.; Alaska, Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo; w Eurasia (including Siberia). Pseudoleskea
patens is a relatively small species that is
usually dull dark green or olive, with short laminal cells with rounded
centrally located papillae. It differs from P. tribulosa by recurved margins,
weaker and lower lamina cell papillae lacking projecting apical salient,
larger leaves with stronger plicae, and lack of the
morningstar-shaped tips of the abaxial apex cells
of the costa. 5. Pseudoleskea
radicosa
(Mitten) Macoun & Kindberg,
Cat. Hypnum
radicosum Mitten.
J. Proc. Linn. Soc., Bot. 8: 31. 1865; Lescuraea
radicosa (Mitten) Mönkemeyer Plants medium to large, in thick mats, green
or yellow-green, orange-green, becoming brown with age. Stems prostrate, with central strand, branches robust, often
julaceous, apices mostly turned up, paraphyllia common, filamentous to
foliose, branched. Leaves ovate to
ovate-lanceolate, asymmetric, appressed to somewhat erect when dry, mostly
falcate to falcate-secund, erect spreading when wet, glossy or dull, lacking hair-point,
0.6--2(--2.4) mm; gradually to abruptly acute to short- or rarely long-acuminate
into short to moderately long acumen, margins narrowly recurved to midleaf or
to near acumen, costa sub-percurrent to percurrent, yellow-green, sometimes
sinuose; median laminal cells pellucid to opaque, homogeneous,
short-rhomboidal, elliptic or fusiform, 2--3(--4):1, mostly less than 40 \um,
thin or rarely firm-walled with lumens more than 10 \um, pellucid to opaque,
prorate to near base, not pitted, laminal cells in acumen similar to proximal
cells, mostly 2--3:1, alar cells distinct in small to medium-sized groups,
transversely elongate to quadrate, smooth, juxtacostal cells similar to
median cells but somewhat shorter than more distal cells, walls not pitted. Capsule cylindric, erect to suberect,
symmetric, 1--2 mm, operculum smooth conic; basal membrane low, 1/4--1/3\x
length of exostome, segments shorter than exostome, cilia usually present, 1--2,
sometimes reduced. Spores 16--22
\um. Varieties 3 (3
in the flora): North America, Eurasia, Pseudoleskea
radicosa is
a common and variable species, with three varieties, two of them quite
distinctive. Pseudoleskea radicosa is
closely related to P. incurvata, but differs in its longer more homogeneous
thin-walled and wider laminal cells. Combined ecological, molecular and
morphological studies of the varieties are needed to determine their
distinctiveness. 1. Plants
large, stem tips hooked, branches few or lacking, leaves 1.6--2.3 mm,
distinctly falcate-secund,
long-acuminate, often multi-plicate ………………………5b.
Pseudoleskea radicosa
var. denudata 1. Plants small to medium, stem tips not distinctly hooked, branches usually numerous, leaves mostly less than 1.6 mm, straight, falcate or falcate-secund, predominantly short acuminate to acute, mostly 2-plicate. 2. Leaves small, distinctly concave, sometimes
incurved, mostly 0.8--1.3 mm, acute
to short-acuminate; branches often julaceous, median laminal cells pellucid ………………………..………………5a.
Pseudoleskea radicosa
var. compacta 2. Leaves medium, somewhat concave, not incurved,
1.2--1.7 mm, long- acuminate,
branches not usually julaceous; median laminal cells opaque ………………………………...…..……5c. Pseudoleskea radicosa var. radicosa 5a. Pseudoleskea
radicosa var. compacta (Best) Lescuraea radicosa
var. compacta (Best) Plants small, bright green. Stems short, branched, branches usually julaceous. Leaves small, mostly 0.8--1.3 mm, strongly concave, often somewhat incurved, abruptly acute to short-acuminate, appressed, not falcate-secund; median laminal cells pellucid, alar cells smooth. Capsules mature summer (June-Aug). Locally common on dry siliceous boulders, rare on calcareous rock and mineral soil, subalpine-alpine; 900--4000 m; Alta., B.C., Nfld. & Labr., Que., Yukon; Ariz., Calif., Colo., Idaho, Oreg., Utah, Wyo.; Europe (Norway). The var. compacta is a
distinctive variety that may be a good species, distinguished by its bright
green color, small size, ovate concave leaves that
often incurve when dry, and clear laminal cells. The 5b. Pseudoleskea
radicosa var. denudata (Kindberg in
Macoun) Wijk & Margadant, Taxon 9: 191. 1960 Pseudoleskea
sciuroides var. denudata Kindberg in
J. Macoun, Cat. Canad. Pl.. Musci, 181. 1892 Plants large, yellow-green to green to
orange-green. Stems with hooked
tips, branches few or lacking. Leaves
large, 1.6--2.3 mm, weakly concave, not incurved, mostly strongly
falcate-secund, long-acuminate; median laminal cells mostly opaque, alar
cells often prorate. Capsules very rare, mature summer (July-Aug). Locally common on mesic soil under shrubs or on boulders, often associated with snow banks, subalpine-alpine; 950--3000 m; Greenland; Alta., B.C.; Alaska, Mont. Wash., Wyo.; w Eurasia; Atlantic Islands (Iceland). The var. denudata is distinctive by its large size, long unbranched stems with hooked tips, strongly falcate-secund leaves, and often multi-plicate lamina. 5c. Pseudoleskea
radicosa var. radicosa Plants medium-sized, yellow-green, green to orange-green. Stems freely and loosely branched, branches julaceous or not. Leaves medium-sized, weakly to moderately concave, not incurved, appressed to somewhat falcate, 1.2--1.7 mm, short to predominantly long-acuminate; median laminal cells mostly opaque; alar cells smooth. Capsules mature summer (July-August). Widespread and common on shaded rocks and outcrops or tree bases, rare on humic soil in forests, subalpine to alpine, 680--3500 m; Greenland; Alta., B.C., Nfld. & Labr., Que., Yukon; Alaska, Calif., Colo., Idaho, Mich., Mont., Nev., N.H., N.M., Oreg., Utah, Wash. Wyo.; Eurasia; Atlantic Islands (Iceland). 6. Pseudoleskea
saviana
(De Notaris) Latzel, Beih.
Bot. Centralblatt 48(2): 499. 1931 Leskea saviana
De Notaris,
Musc. Ital. Spic., 8. 1837; Lescuraea saviana (De Notaris) Plants small to medium, in thin open to thick
mats, green or yellow-green, becoming brown with age. Stems prostrate, with central strand, branches robust, often
julaceous, apices mostly turned up, paraphyllia common, filamentous to
foliose, not branched. Leaves ovate-lanceolate
to lanceolate, asymmetric, appressed to somewhat erect when dry, more or less
falcate, erect spreading when wet, glossy or dull, lacking hair-point,
0.9--1.2 mm; abruptly long-acuminate into slender acumen, margins strongly
and broadly recurved to acumen, costa sub-percurrent to percurrent, green to
yellow-green, sometimes sinuose; median laminal cells opaque,
elongate-rhomboidal to fusiform or somewhat vermicular, 3--4:1, mostly less
than 25 \um long, firm-walled to incrassate, strongly prorate to near base,
not pitted, laminal cells in acumen similar to proximal cells, alar cells
distinct in large groups, transversely elongate to quadrate, smooth, juxtacostal
cells similar to median cells but somewhat longer than cells above, walls not
pitted. Capsule cylindric, erect
to suberect, symmetric, 1--1.5 mm, operculum smooth conic; basal membrane
low, 1/3\x length of exostome, segments shorter than exostome, cilia lacking
or rudimentary. Spores 12--17 \um. Sporophytes mature spring-summer (May-Aug). Locally uncommon on bases of tree trunks, or boulders and outcrops, rarely on soil at moderately high elevations, descending to somewhat lower elevations in northern portion of range; (600--)1000--2500 m; Alaska (Aleutian Islands), Calif., Idaho, Wash.; w Eurasia. Pseudoleskea saviana is characterized by its strongly recurved margins to near the acumen, the relatively long, slender median leaf cells, the somewhat longer proximal juxtacostal cells, and a long-acuminate acumen that is often as long as the rest of the lamina. 7. Pseudoleskea stenophylla Renauld & Cardot in Röll, Bot. Centralblatt 44: 21. 1890 Lescuraea stenophylla (Renauld
& Cardot) Kindberg Plants small in thin open to thick mats,
green or yellow-green, becoming brown with age. Stems prostrate, with central strand, branches slender, not or
rarely julaceous, apices mostly straight to rarely turned
up, paraphyllia common, filamentous to foliose, not branched. Leaves ovate-lanceolate to
lanceolate, symmetric, appressed to somewhat erect when dry, erect spreading
when wet, not or rarely falcate except at tips, glossy, lacking hair-point,
0.9--2 mm; gradually long-acuminate into slender acumen, margins recurved
proximally to just before acumen, costa percurrent, green to yellow-green,
not sinuose; median laminal cells pellucid, elongate-rhomboidal to fusiform
or somewhat vermicular, 2--3 (4):1, mostly less than 30 \um, firm-walled to
incrassate, strongly papillose over lumen, papillae usually off-centered to
distal edge, rarely some cells prorate; not pitted, laminal cells in acumen
similar to proximal cells, alar cells distinct in small groups, transversely
elongate to quadrate, smooth, juxtacostal cells similar to median cells but
somewhat shorter than more distal cells, walls not pitted. Capsule cylindric, erect, symmetric,
1--3 mm, operculum smooth conic; basal membrane low, 1/4\x length of
exostome, segments shorter than exostome, cilia lacking or rudimentary. Spores 16--20 \um. Sporophytes mature spring-summer (May-Aug). Locally uncommon on twigs and branches of shrubs or small trees including tree bases, primarily of Alnus or Acer along streams; 500-2100 m; Alta, B.C., N.S., Nfld. & Labr., Que.; Alaska, Calif., Idaho, Oreg., Mont., Utah, Wash.; w Eurasia. Pseudoleskea stenophylla is distinguished as small plants growing on bark and twigs of shrubs and trees, leaves with a long, slender acumen comprising up to half the leaf length, and elongate laminal cells with papillae over the lumen but usually off-centered. 8. Pseudoleskea
tribulosa
Shevock & W. R. Buck, Bryol. 112: 184. 2009 Plants small, in slender mats, dark green or
olive-green. Stems prostrate, with
central strand, branches slender, not julaceous, mostly prostrate, tips rarely curved up, paraphyllia common, foliose, not
branched. Leaves oblong-ovate,
more or less symmetric, catenulate, weakly incurved dry, erect spreading when
wet, not falcate, dull, lacking hair-point, 0.6--0.9 mm; gradually acute to
broadly acuminate, margins plane; costa not reaching acumen to subpercurrent,
green to orange-green, not sinuose, abaxial cells at apex projecting in a morningstar-like pattern; median laminal cells pellucid,
predominantly quadrate to isodiametric, 1:1, mostly less than 10 \um,
incrassate, strongly mammillose-papillose over lumen or rarely off-centered,
papillae often with apical cell pointed, covering most of lumen; laminal cell
walls not pitted, cells in acumen similar to proximal cells, alar cells
distinct in large groups, quadrate to transversely elongate, proximal juxtacostal
cells similar to median cells but mostly shorter, walls pitted or not. Capsule unknown. Rare on shaded metamorphosed limestone overhangs and boulders, 2600--2900 m; Calif. Endemic. Of conservation concern. Pseudoleskea tribulosa is
a distinctive endemic species only known from a few sites in the subalpine
zone of |
