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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 in
median and distal regions, smooth or distal cells sometimes prorulose at
distal ends on abaxial surface, 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,
Plants of this
genus occur in terrestrial habitats in temperate, subtropical and tropical
regions. SELECTED
REFERENCES 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) 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 ( 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; distal cells sometimes prorulose at upper ends on abaxial
surface; 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 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 Müller
Hal.; 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;
distal cells sometimes minutely prorulose at upper ends on abaxial surface;
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.,
Del., Ga., Idaho, Ill., Ind., Ky., Maine, Md., Mich., Minn., 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 |
