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BFNA Title: Leptostomopsis |
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XX.
LEPTOSTOMOPSIS (Müller Hal.) J. R. Spence & H. A. Ramsay, Phytologia 87:
70, 2005 * [The genus Lepstostomum, Greek lepto, small, and stoma,
mouth, alluding to the capsule opening] John R. Spence Plants small, in dense cushions,
turfs or rarely gregarious, pale green-silver, pinkish or yellow-silver. Stems short, 0.4--2 cm, sometimes
julaceous, strongly branching by subfloral innovations, stolons absent;
rhizoids abundant, micronemata and macronemata present on stems. Leaves imbricate dry, erect to
erect-spreading when wet, broadly ovate to spathulate, somewhat concave,
0.4--2.5 mm, base straight or slightly curved at insertion, not decurrent;
margins plane distally, recurved proximally or sometimes plane, 1-stratose,
nearly smooth to distinctly serrate near apex, limbidium present or absent,
apex broadly rounded to acute, sometimes hyaline, costa long-excurrent as a denticulate
to spinose hyaline awn, sometimes branched at tip, costa transverse section
with one well-developed stereid band, guide cells present; adaxial
supracostal cells irregularly to regularly quadrate or short-rectangular at
base, laminal cells heterogeneous, proximal cells usually quadrate to
short-rectangular, medial cells generally similar to distal cells, distal
cells hexagonal to rhomboidal, 3--6:1, occasionally longer, not in rows
oblique to the costa, thin- to thick-walled, walls not pitted, alar cells
usually distinct in quadrate groups or sometimes transversely elongate in
small groups. Specialized asexual
reproduction absent. Sexual
condition dioicous; perigonia and perichaetia terminal, leaves the same
size as vegetative leaves or typically larger, not forming a rosette, inner
leaves little differentiated. Seta
usually 1, straight to somewhat twisted. Capsule
erect, 2--5 mm, cylindrical, hypophysis well-differentiated, somewhat
expanded and rugose, exothecial cells near mouth quadrate or
short-rectangular, thick-walled, reddish, in 1--2 rows, proximal cells
longer, irregularly long-rectangular
with straight or sinuose walls; annulus usually present, revoluble; operculum
weakly convex, short-conic, not rostrate; peristome diplolepidous-alternate,
exostome pale yellow or tan, sometimes reddish, teeth slender lanceolate, not
trabeculate, lacking pores along fissural line, endostome hyaline to pale
yellow, separate or sometimes adherent to exostome, segments absent, basal
membrane low to high, cilia absent. Calpytra
fugacious, cucullate, small, smooth. Spores
shed singly, not as tetrads, not germinating in capsule, 12--50 \um, finely
papillose, pale tan, yellow-tan or brown. Species
10 (2 in the flora). Southern North America, Mexico, Central and Southern
America, Southeast Asia, Java, Africa, India, mostly subtropical to tropical
seasonal environments. Leptostomopsis is a distinctive genus superficially similar to Leptostomum. Recent molecular work suggests that it is
basal to the remainder of the Bryaceae. It was originally included in the
polyphyletic Brachymenium. Although the molecular work indicates that
the genus should be placed in the Bryaceae, morphologically it is close to Leptostomum
and a case could be made for moving it to the Leptostomaceae. SELECTED
REFERENCES: Andrews, A. L. 1935. Bryaceae. In: A. J. Grout, Moss flora of 1.
Leaves silver-yellow, distal half to third of lamina and awn hyaline, distal
lamina cells elongate, 4--6:1, thick walled and usually somewhat sinuose
...........................................................1. Leptostomopsis
nivea 1.
Leaves pale green or green-silver, lamina green distally, proximal portion of
awn colored, usually brown or red-brown, sometimes with pinkish tinge, distal
laminal cells shorter and wider, 3--4:1, not thick walled or sinuose
...........................................................................................2.
Leptostomopsis systylia 1. Leptostomopsis nivea (Bescherelle) J. R. Spence [unpublished as yet] Brachymenium niveum Bescherell, J. de Bot. (Morot) 15: 383. 1901 Plants in dense cushions, turfs or
gregarious, pale yellow-silver. Stems
very short, 0.4--0.8 cm. Leaves
imbricate when dry, erect to erect-spreading when wet, broadly ovate,
somewhat concave, 0.2--1 mm; margins serrate near apex, limbidium present
distally, apex acute, hyaline, costa excurrent as long-excurrent denticulate
to spinose hyaline awn, straight to weakly recurved when dry, laminal cells
heterogenous, proximal cells usually quadrate to short-rectangular, distal cells hyaline, rhomboidal to almost
vermicular, 30--40 \um, 4--6:1, thick-walled and somewhat sinuose. Sexual condition dioicous. Seta straight to somewhat twisted,
reddish brown to yellow. [Capsule
erect, 2--3 mm, oblong, hypophysis slender, inconspicuous to somewhat
well-differentiated, sometimes expanded and rugose, endostome hyaline to pale
yellow, separate or rarely adherent to exostome, segments absent, basal
membrane low, cilia absent. Spores
20--23 \um, finely papillose, pale yellow-tan or brown.] Sporophytes unknown
in flora area. Rare on dry volcanic rock and sandy soil; 1000--1200 m,
Madrean woodland in canyons, rarely on open playa edges; Leptostomopsis nivea was recently collected from
two locations in southeastern 2. Leptostomopsis systylia (Müll. Hal.) J. R. Spence, Phytologia 87: 70,
2005 Brachymenium systylium Müll. Hal., Syn. Musc. Frond. 1: 320. 1848 Plants in dense cushions or turfs,
green-silver to pink-silver. Stems
short, 0.4--2 cm, sometimes julaceous. Leaves
imbricate when dry, erect when wet, spathulate to somewhat elongate-ovate,
concave, 0.3--2 mm, margins plane distally, recurved proximally, serrulate to
serrate near apex, limbidium absent, apex broadly rounded to acute, not
hyaline, costa percurrent in proximal leaves to long-excurrent as a denticulate
to spinose awn distally, weakly to strongly recurved when dry, awn tip
hyaline but colored proximally, medial cells generally similar to distal
cells, distal cells hexagonal to rhomboidal, 40--60 \um, 3--4:1, occasionally
longer, not distinctly thick-walled or sinuose, greenish. Sexual condition dioicous. Seta straight to somewhat twisted,
reddish-brown to yellow. [Capsule
erect, 2--4 mm, cylindrical, hypophysis well-differentiated, somewhat
expanded and rugose, endostome hyaline to pale yellow, separate or rarely
adherent to exostome, segments absent, basal membrane low, cilia absent. Spores 17--25 \um, finely papillose,
pale yellow-tan or brown.] Sporophytes unknown
in flora area. Uncommon on trunks of trees, especially Quercus,
occasionally on rock or soil; 0--2000 m, Ariz., Fla., N.Mex., N.C., Tex.;
Mexico, Central America; South America; tropical Africa; se Asia (including
India, Java). A pantropical-subtropical species. The shiny pale
yellow-green to pink-tinged plants of Leptostomopsis systylia are found primarily on tree
trunks. This species is much more
common and widespread than L. nivea, and the two can be readily
distinguished by laminal cell differences.
Recently, material of what appears to be a third Leptostomopsis
has been collected from rock in |
