BFNA Title: Pseudotaxiphyllum
Author: R. R. Ireland
Date: August 7, 2003
Edit Level: R Brum +
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

BFNA Web site: http://www.mobot.org/plantscience/BFNA/bfnamenu.htm

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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, 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; 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 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.

 

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 Texas, and a new species of Isopterygium.  Bryologist 76(3): 440--442.