Fissidens dubius |
Fissidens appalachensis |
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fissidens moss |
Appalachian fissidens moss |
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Habit | Plants to 25 × 3.5 mm. | Plants to 13 × 2–4 mm. |
Stem | usually branched; axillary hyaline nodules absent; central strand present. |
unbranched and branched; axillary hyaline nodules weak or absent; central strand weak. |
Leaves | as many as 25 pairs, often undulate, oblong to lanceolate, obtuse to acute, often apiculate, to 3.5 × 0.7 mm; dorsal lamina truncate-rounded proximally, ending at insertion, not decurrent; vaginant laminae 2/3 the leaf length, ± unequal, minor lamina ending near margin; margin crenulate to crenulate-serrulate but unevenly serrate at leaf apex, elimbate; costa ending a few cells before apex to percurrent, taxifolius-type; laminal cells irregularly 2-stratose in dorsal and ventral laminae, ± obscure, smooth, bulging, firm-walled, rounded-hexagonal, 7–10 µm, 3–4 rows of marginal cells thinner, walls slightly thicker, forming a pale marginal band. |
as many as 22 pairs, ligulate to oblong-lanceolate, obtuse-mucronate to acute, to 4 × 0.3–0.5 mm; dorsal lamina narrowed proximally, ending at insertion or slightly before; vaginant laminae 1/2–2/3 leaf length, equal in proximal leaves, unequal in distal leaves, minor lamina ending between margin and costa or rounded and ending on or near costa; margin entire but sometimes serrulate distally, limbate on all laminae, limbidium confluent at apex or ending a few cells before, limbidial cells 2- to 5-stratose; costa percurrent or ending in mucro, bryoides-type; laminal cells 1- to irregularly 2-stratose, smooth, slightly bulging, firm-walled, irregularly hexagonal, many somewhat elongate, 10–16 µm, juxtacostal and basal cells of vaginant laminae somewhat larger, quadrate to oblong. |
Seta | to 11 mm. |
4–4.5 mm. |
Sexual condition | dioicous; perigonia on short axillary branches and elongate stems; perichaetia on short axillary branches, mostly near proximal ends of stems. |
rhizautoicous or synoicous; perigonia and perichaetia on elongate stems. |
Capsule | theca slightly inclined, slightly arcuate, bilaterally symmetric, to 1.8 mm; peristome taxifolius-type; operculum 1–1.4 mm. |
theca exserted, erect, radially symmetric to slightly inclined, bilaterally symmetric, 0.6–0.85 mm; peristome bryoides-type; operculum 0.4 mm. |
Calyptra | cucullate, smooth, 1.8 mm. |
not seen. |
Spores | 13–20 µm. |
14–25 µm. |
Sporophytes | 1 per perchaetium. |
1–2 per perichaetium. |
Fissidens dubius |
Fissidens appalachensis |
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Habitat | Soil and humus, bases of trees, decaying wood, rocks and boulders in moist, shaded sites | Crevices and surfaces of rocks submerged in swiftly flowing but usually shallow water, sometimes partially emergent |
Distribution |
AK; AL; AR; AZ; CA; CT; DE; FL; GA; IA; IL; IN; KS; KY; MA; ME; MI; MN; MO; MS; NC; NE; NH; NY; OK; PA; SC; TN; TX; VA; VT; WI; WV; NB; NF; NS; ON; QC; Mexico; Central America; West Indies; Europe; Asia; Pacific Islands
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NC; PA; SC; TN |
Discussion | In contrast to Fissidens adianthoides, F. dubius has smaller, irregularly 2-stratose, obscure laminal cells. Subterranean, irregularly globose, multicellular rhizoidal gemmae have been reported for F. dubius as well as F. osmundioides and F. taxifolius in Europe and Japan. Z. Iwatsuki and T. Suzuki (1982) cited the occurrence of dwarf male plants (small perigonial stems located on the leaves of perichaetial plants) in Japanese specimens. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Fissidens appalachensis, restricted to rapidly moving water, is distinguished by its habitat and strong limbidium. It is most likely to be confused with an expression of F. bryoides that is usually found on wet rocks and stones along the edges of streams, but which differs in its smaller size and weaker limbidium that at times can be partially or completely absent. Laminal cells in size and shape, vaginant laminae, sexuality, thecae, and peristomes in both taxa are similar. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 340. | FNA vol. 27, p. 344. |
Parent taxa | Fissidentaceae > Fissidens | Fissidentaceae > Fissidens |
Sibling taxa | ||
Synonyms | F. adianthoides var. semicristatus, F. cristatus, F. cristatus var. winonensis, F. decipiens var. winonensis, F. floridanus | |
Name authority | P. Beauvois: Prodr. Aethéogam., 57. (1805) | R. H. Zander: Bryologist 72: 406, figs. 1–8. (1969) |
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