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BFNA Title: Pseudotaxiphyllum |
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Pseudotaxiphyllum - Hypnaceae XXX. PSEUDOTAXIPHYLLUM Z. Iwatsuki, J. Hattori
Bot. Lab. 63: 448. 1987 * [Greek pseudo,
false + Taxiphyllum, a genus of mosses in the Hypnaceae] Robert
R. Ireland Plants medium-sized, in
thin to dense, often complanate, light- to yellowish-green, dull to glossy
mats. Stems 1.5--3.5 cm,
creeping, simple or sparingly and irregularly branched, cortical cells small,
thick-walled, central strand sometimes present; rhizoids smooth, in clusters
proximal to leaf insertions; axillary hairs not observed; pseudoparaphyllia
lacking. Leaves of stem and
branches similar, somewhat rigid, crowded and imbricate, erect-spreading to
squarrose, sometimes upturned-homomallous, often complanate, smooth or
undulate, flat or concave, symmetric to asymmetric, not decurrent,
lanceolate, ovate, ovate-lanceolate or oblong-lanceolate, acute, sometimes
abruptly so, to acuminate; margins plane to erect, serrate to serrulate;
costa short and double or lacking; cells firm-walled, often flexuose,
linear-fusiform, smooth, walls not pitted; alar regions not or distinctly
differentiated with numerous quadrate to short-rectangular cells. Specialized asexual reproduction by
multicellular bodies sometimes present in clusters at stem apices or below in
leaf axils, elongate, smooth-celled, twisted-vermiform, with 1--5 acute
teeth, 0.1--0.5 mm, or resembling parent plant but smaller, bearing reduced
leaves from apex to base of propagula, 0.5--1.5 mm. Sexual condition dioicous or sometimes autoicous,
usually sterile; perigonia along stems, perichaetia at base of stems, bracts
small, lanceolate to ovate, acuminate to abruptly filiform-acuminate, margins
plane. Seta smooth, elongate,
straight or sometimes curved, twisted, red to reddish brown. Capsule cernuous to pendulous,
straight to subarcuate, dark brown to dark red, smooth to wrinkled,
contracted below mouth and wrinkled at neck when dry; opercula conic to
short-rostrate, shorter than urn; annulus present, deciduous, of 2–3
rows of cells; peristome double, exostome teeth cross-striolate proximally, papillose
distally, bordered, trabeculate on interior; endostome with a high to low
basal membrane, keeled segments and cilia shorter than the segments, in
groups of 1--3. Calyptra cucullate,
smooth, naked. Spores spherical
to ovoid, minutely papillose. Species 10 (3 in the flora): North America,
Central America, South America, Europe, Africa, Asia. Plants of this genus occur in terrestrial
habitats in temperate, subtropical and tropical regions. SELECTED REFERENCES Ireland, R.R.
1969. A taxonomic revision of
the genus Plagiothecium for North America, north of Mexico. National Museums of Canada, Nat. Mus. Nat.
Sciences, Publs. in Botany, No. 1: 1--118.
Iwatsuki, Z. 1987. Notes on Isopterygium Mitt.
(Plagiotheciaceae). J. Hattori Bot.
Lab. 63: 445--451. 1. Leaves upturned-homomallous; median leaf
cells broad, often more than 5 µm wide; propagula lacking . . . . 1. Pseudotaxiphyllum
homomallifolium l. Leaves not upturned-homomallous; median
leaf cells narrow, usually 5 µm or less wide; propagula present. 2. Leaves asymmetric, often cultriform;
propagula clustered at stem apices and in distal leaf axils, elongated,
twisted-vermiform, with 1--5 acute teeth at apices . . . 2. Pseudotaxiphyllum
distichaceum 2. Leaves symmetric, never cultriform;
propagula clustered in leaf axils below stem apices, resembling parent plant
but smaller, bearing reduced leaves from apex to base of propagula . . . .
3. Pseudotaxiphyllum elegans 1.
Pseudotaxiphyllum homomallifolium (Redfearn)
Ireland, Caldasia 16 (78): 267. 1991 Isopterygium homomallifolium
Redfearn, Bryologist 76: 440. 1973 Plants in thin to dense
mats, yellowish green, glossy. Stems
to 15 × 1--2 mm, simple or
irregularly branched. Leaves semi-flaccid
to rigid, distant to close and overlapping, erect-spreading,
upturned-homomallous, occasionally complanate, smooth, 0.8--1.2 ×
0.3--0.5 mm, lanceolate to ovate-lanceolate, symmetric, long-acuminate;
margins plane, serrulate nearly to base; costa weak, short and double or
lacking; cells smooth, 60--120 ×
5--9 µm; alar cells poorly differentiated, a few short-rectangular cells
often present. Specialized asexual
reproduction lacking. Sexual
condition autoicous. Seta
yellow to reddish, 0.8--1.6 cm. Capsule
erect to horizontal, slightly cernuous, 1.4--1.7 mm, ellipsoid, contracted
below the mouth when dry; operculum high-conic to short-rostrate, 0.4--0.6
mm. Spores 9--16 µm. Capsules mature spring--summer. Rocks and under rock ledges; 1370--1920 m;
Ariz. (Cochise, Navajo, Santa Cruz Cos.), Tex. (Kimble Co.), N. Mex. (Dona
Ana Co.); Mexico (Sonora). Pseudotaxiphyllum homomallifolium
is readily distinguished from the other two species of the genus by the
long-acuminate, upturned-homomallous leaves with broad leaf cells. The species somewhat resembles a Campylium
but the leaf apices are not channeled like the leaves of species in that
genus. Foliose pseudoparaphyllia were attributed to P. homomallifolium
when P. L. Redfearn (1973) described the species but I do not believe they
should be classified as those structures.
The multicellular structures rarely found on the stems seem to be part
of a developing branch primordium because they do not appear to be distinctly
separated from the rest of the primordium, sometimes are not even evident,
and they are not on the stems at the bases of mature branches as are typical
pseudoparaphyllia. 2.
Pseudotaxiphyllum distichaceum (Mitten) Z.
Iwatsuki, J. Hattori Bot. Lab. 63: 449.
1987 Stereodon distichaceus
Mitten, J. Proc. Linn. Soc., Bot., Suppl. 1: 105. 1859; Isopterygium distichaceum (Mitten) A.
Jaeger; Isopterygium subfalcatum (Austin) A. Jaeger; Plagiothecium
subfalcatum Austin; Taxiphyllum howellianum H.A. Crum & L.E.
Anderson Plants in thin, loose mats,
light- to yellowish green, glossy. Stems
to 25 × 1--3 mm,
complanate, simple or irregularly branched.
Leaves semi-flaccid to rigid, distant, squarrose, complanate,
smooth, 0.3--1.8 × 0.2--0.6 mm, ovate-
or oblong-lanceolate, often cultriform, asymmetric, acuminate; margins plane
or narrowly recurved at base, serrate to serrulate distally, serrulate to
entire proximally; costa usually strong, short and double; median cells
smooth, 48--100 × 4--7 µm; alar cells
undifferentiated or 1--3 marginal cells quadrate to rectangular. Specialized asexual reproduction often
present as twisted-vermiform bodies clustered in leaf axils at or near stem
apices, 0.1--0.5 mm, yellowish green, elongate, composed of 2--4 layers of
smooth cells, with 1--5 acute, erect teeth at apex. Sexual condition autoicous. [Seta to 1 cm. Capsule
horizontal, ovoid, ca. 1.3 mm; operculum conic. Spores not reported.] Sporophytes unknown in North America. Soil, humus banks, sandstone bluffs, and frequently
on cliff ledges containing mica; 135--1675 m; N.B., Nfld, N.S., Ont., Que.;
Ark., Ga., Ill., Ind., Ky., Maine, Md., Mich., Mo., N.J., N.Y., N.C., Ohio,
Pa., S.C., Tenn., Vt., Va., W.Va.; Mexico (Jalisco, Veracruz, Zacatecas);
West Indies (Dominican Republic); Central America (Costa Rica); South America
(Brazil, Colombia, Ecuador, Venezuela); Asia; Australia. Pseudotaxiphyllum distichaceum is
easily confused with P. elegans, especially when propagula are
not present. The asymmetric, often
cultriform leaves of P. distichaceum will distinguish it from P.
elegans, which has symmetric leaves that are never cultriform. When propagula are present, their location
on the stems, as well as their morphology, are distinctly different in the
two species. Pseudotaxiphyllum
distichaceum has propagula that are elongate, twisted-vermiform with
1--5 acute teeth at the apices, and occur in the leaf axils at or near the
stem apices; while P. elegans has propagula in the leaf axils
always below the stem apices, and they resemble the parent plant, being much
smaller, possessing small leaf-like structures along their stems. 3.
Pseudotaxiphyllum elegans (Bridel) Z.
Iwatsuki, J. Hattori Bot. Lab. 63: 449.
1987 Hypnum elegans
Hooker, Musci Exot. 1: Pl. 9. 1818,
illegitimate name; Isothecium elegans Bridel, Bryol. Univ. 2:
356. 1827; Hypnum borrerianum
J.K.A. Müller; Isopterygium elegans (Bridel) Lindberg; Plagiothecium
elegans (Bridel) Schimper; P. elegans var. gracilens (Grout)
H. A. Crum, Steere & L.E. Anderson; P. elegans var. schimperi
(Juratzka & Milde) Limpricht; P. elegans var. terrestre
(Lindberg) Rau & Hervey Plants in thin to dense
mats, dark-to yellowish green, glossy.
Stems to 35 × 1.0--2.5 mm,
complanate, simple or irregularly branched.
Leaves semi-flaccid to rigid, close to somewhat distant,
erect-spreading or sometimes secund with apices pointing toward substratum,
somewhat concave, smooth, 0.3--2.0 ×
0.2--0.7 mm, lanceolate, ovate- or oblong-lanceolate, symmetric, acuminate;
margins plane, serrulate to strongly serrate distally, serrulate to entire
proximally; costa usually strong, short and double; median cells smooth,
48--100 × 4--7 µm; alar cells
undifferentiated or 1--3 quadrate to rectangular cells on margins. Specialized asexual reproduction present
as propagula clustered in leaf axils below stem apices, 0.5--1.5 mm, yellow
to green, smooth-celled, resembling the parent plant but smaller, bearing
reduced leaves from apex to base of stems.
Sexual condition dioicous.
Seta dark red, 1.0--2.5 cm.
Capsule cernuous to pendulous, straight or subarcuate, 1--2 mm,
oblong-ovoid to ovoid, wrinkled and contracted below mouth when dry;
operculum conic to short-rostrate, 0.4--0.7 mm. Spores 7--12 µm. Capsules mature spring--summer. Woods, acidic rock and soil, humus, bases
of trees, and rotten logs; 0--1980 m; B.C., N.B., Nfld., N.S., Ont., P.E.I.,
Que., Yukon; Alaska, Ala., Ark., Calif., Conn., Ga., Idaho, Ill., Ind., Ky.,
Maine, Md., Mich., Mo., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., S.C.,
Tenn., Vt., Va., Wash., W.Va..; South America (Argentina). This species is distinguished by the close to
somewhat distant, erect-spreading, lanceolate, ovate- or oblong-lanceolate,
symmetric, acuminate leaves with serrulate to strongly serrate margins, the
narrow median leaf cells, the poorly differentiated alar cells, 1–3
marginal cells quadrate to rectangular, and the presence of clusters of
propagula in the leaf axils below stem apices, the propagula resembling the parent
plant but smaller, bearing reduced leaves on the stems from apex to base. Pseudotaxiphyllum
elegans is morphologically close to P. distichaceum. For distinctions see discussion of that
species. OTHER REFERENCES Redfearn,
P.L., Jr. 1973. Additions to the moss flora of Texas, and
a new species of Isopterygium.
Bryologist 76(3): 440--442. |
