Fissidens amoenus Müll.Hal.
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Authority
Pursell, Ronald A. 2007. Fissidentaceae. Fl. Neotrop. Monogr. 101 (Published by NYBG Press)
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Family
Fissidentaceae
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Scientific Name
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Type
Type. Brazil. Sa. Catharina [Santa Catarina]: without locality, Pabst s.n. (neotype, S, selected by Pursell, 1994c). The original collection of this species, which could not be located, was collected by Moritz in Caripe, Venezuela.
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Synonyms
Conomitrium amoenum (Müll.Hal.) Müll.Hal., Fissidens hallii Austin, Conomitrium platybryoides Müll.Hal., Fissidens platybryoides Müll.Hal., Fissidens catharinensis Paris, Fissidens platyphyllus Broth., Fissidens orcuttii Grout, Fissidens tamaulipasensis Pursell
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Description
Species Description - Plants pale green. Stems monomorphic, unbranched, 1.5-5 mm long x 1.5-3.0 mm wide; rhizoids basal, smooth, reddish; axillary hyaline nodules absent; epidermis and outer tier of cortical cells small, incrassate, pigmented; inner cortical cells larger, thin-walled, hyaline; central strand present. Leaves ± crispate when dry, loosely imbricate, many as 8 pairs, sometimes palmately arranged, lanceolate, acute, to 3 mm long x 0.3 mm wide, perichaetial leaves usually longest; margin serrate, often coarsely so on vaginant laminae, limbate on vaginant laminae of perichaetial leaves, limbidial cells unistratose; costa ending 2-4 cells below apex to percurrent, bry-oides type; dorsal lamina narrowed to insertion; vaginant laminae of cauline leaves ± 1/2 leaf length, acute, unequal, minor lamina ending ± halfway between costa and margin to ending near leaf margin; laminal cells distinct, eguttulate, unistratose, firm-walled, bulging, irregularly hexagonal, 7.5-13 µm long, larger, oblong, pellucid in juxtacostal patches in lower parts of vaginant laminae. Monoicous (rhizau-toicous); perigonial stems gemmiform around base of perichaetial stems. Sporophytes 1 per perichaetium, yellow, darkening with age; seta smooth, 3-6 mm long; theca exserted, erect, radially symmetric, 0.30.5 mm long, stomatose, exothecial cells quadrate, collenchymatous; peristome bryoides type; operculum to 0.5 mm long. Spores smooth, 7-10 µm diam. Calyptra ± prorate, cucullate, 0.4 mm long.
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Discussion
Fissidens amoenus is distinguished by a limbidium of unistratose cells restricted to the vaginant laminae of perichaetial leaves, smooth laminal cells, enlarged, oblong, pellucid juxtacostal cells in the proximal parts of the vaginant laminae, and a typical bryoides type peristome. It is most likely to be confused with F. obtussisimus, F. pellucidus, F. serratus, and F. zollingeri in subgenus Aloma, which are characterized by a scariosus type peristome. The leaves of F. serratus are usually elimbate, the marginal cells, especially those on the vaginant laminae, are usually coarsely serrate, and the laminal cells are unipapillose. The smaller and eguttulate laminal cells of F. amoenus will distinguish the species from F. pellucidus. The. laminal cells, in particular, the large, pellucid cells in the lower parts of the vaginant laminae of F. amoenus are similar to those seen in F. zollingeri, but the leaves of this species are limbate on all laminae. Fissidens amoenus might also be confused with F. obtusissmus, but the plants of this species are typically larger, a limbidium occurs along the entire margin of the vaginant laminae of most or all of the broad, obtuse, apiculate leaves, and the setae are shorter.
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Distribution
Mexico (Tamaulipas); Central America (Costa Rica); South America (Brazil, Ecuador, Uruguay, Venezuela); on soil and tree bark; 50-2600 m. The species also occurs in the United States (Florida, Louisiana, North Carolina, Texas).
Rio Grande do Sul Brazil South America| Heredia Costa Rica Central America| Puntarenas Costa Rica Central America| Trujillo Venezuela South America| Morona-Santiago Ecuador South America| Montevideo Uruguay South America|