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fissidens moss, yew-leaf pocket moss

blunt-leaf pocket moss, obtuseleaf fissidens moss

Habit Plants to 11 × 3.5 mm. Plants to 8 × 1.5 mm.
Stem

mostly branched;

axillary hyaline nodules absent;

central strand present.

branched;

axillary hyaline nodules absent;

central strand weak or absent.

Leaves

as many as 15 pairs, often undulate, oblong to lanceolate, obtuse to broadly acute, cuspidate, to 2.7 mm × 0.6 mm;

dorsal lamina truncate-rounded proximally, ending at insertion, not decurrent;

vaginant laminae 2/3 the leaf length, ± equal, minor lamina ending on or near margin;

margin evenly serrulate, often crenulate-serrulate on dorsal and ventral laminae, elimbate;

costa ending in cuspidate apex, taxifolius-type;

laminal cells 1-stratose, distinct, smooth, bulging, firm-walled, irregularly hexagonal, 8–11 µm frequently paler at margin, conspicuously mammillose in vaginant laminae, larger and clearer juxtacostally.

as many as 20 pairs, broadly ovate to oblong, rounded to obtuse, infrequently weakly apiculate in distal leaves, to 1.3 × 0.4 mm;

dorsal lamina narrowed proximally, ending at or before insertion;

vaginant laminae ± 1/2–4/5 leaf length, ± equal, minor lamina ending on or near margin;

margin ± entire, elimbate or weakly to strongly limbate, limbidium restricted to proximal parts of vaginant laminae of perichaetial, perigonial and subtending leaves, or present along entire length of vaginant laminae of most leaves, or variable on all laminae of larger leaves, often intralaminal in proximal parts of vaginant laminae, often spurred in vaginant laminae;

costa ending 2–11 cells before apex, often spurred above, bryoides-type;

laminal cells 1-stratose, distinct, smooth, ± bulging, irregularly quadrate to hexagonal, 6–15 µm.

Seta

to 17 mm.

to 3.5 mm.

Sexual condition

rhizautoicous;

perigonia on short branches proximal to elongate stems;

perichaetia on short, proximal, axillary branches.

cladautoicous, gonioautoicous, and possibly rhizautoicous;

naked archegonia occasionally in axils of distal leaves.

Capsule

theca slightly inclined, slightly arcuate, bilaterally symmetric, to 1.5 mm;

peristome taxifolius-type;

operculum to 1 mm.

theca exserted, ± erect, radially symmetric, to 0.8 mm;

peristome bryoides-type;

operculum to 0.3 mm.

Calyptra

cucullate, smooth, to 2 mm.

cucullate, smooth, 0.5 mm.

Spores

13–18 µm.

20–29 µm.

Sporophytes

1 per perichaetium.

1 per perichaetium.

Fissidens taxifolius

Fissidens obtusifolius

Habitat Damp, shaded soil, humus, and rocks Typically on limestone and limestone bearing sandstone along streams and waterfalls, often near the high-water level, sometimes inundated, infrequently on bricks
Distribution
from FNA
AL; AR; AZ; CA; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; ME; MI; MO; MS; NC; NE; NH; NJ; NY; OH; OK; OR; PA; SC; TN; TX; VA; VT; WA; WI; WV; NS; NT; ON; PE; QC; Mexico; Central America; West Indies; South America (Brazil and Chile); Europe; Asia (China, Japan); Pacific Islands (New Zealand)
[WildflowerSearch map]
from FNA
AL; AR; CO; CT; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; NE; NY; OH; OK; PA; TN; TX; UT; VA; WI; WV; ON
[WildflowerSearch map]
Discussion

Fissidens taxifolius is distinguished by evenly serrulate or crenulate-serrulate leaf margin, stout costa ending in leaf cusp, conspicuous mammillose cells in the vaginant laminae, and sporophytes on short branches in the axils of proximal leaves. It can be confused with F. bushii, but that species is smaller, has costa shorter, and cells in the vaginant laminae have small, more or less inconspicuous papillae in the corners of the walls. Fissidens taxifolius usually occurs on shaded, damp soil or humus, whereas F. bushii is usually found on disturbed soil in woods, along paths, and in road cuts. Fissidens clebschii is considered to be a freakish expression of F. taxifolius (R. A. Pursell 2003).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The ovate to oblong, rounded to broadly obtuse leaves on which the limbidium can be quite variable distinguish Fissidens obtusifolius. It has been confused with an expression of F. bryoides that typically occurs on acidic stones and rocks aside streams, and with expressions of F. sublimbatus (R. A. Pursell 1997). Both of those species have highly variable limbidia. The former, however, has lanceolate to ligulate, acute to obtuse-apiculate leaves in which the apiculus is poorly developed. The latter has smaller laminal cells and ovate to lanceolate, rounded to obtuse-apiculate leaves in which the apiculus is a single sharply pointed cell.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 27, p. 341. FNA vol. 27, p. 348.
Parent taxa Fissidentaceae > Fissidens Fissidentaceae > Fissidens
Sibling taxa
F. adianthoides, F. amoenus, F. aphelotaxifolius, F. appalachensis, F. arcticus, F. asplenioides, F. bryoides, F. bushii, F. closteri, F. crispus, F. curvatus, F. dubius, F. elegans, F. exilis, F. fontanus, F. grandifrons, F. hallianus, F. hyalinus, F. leptophyllus, F. littlei, F. minutulus, F. obtusifolius, F. osmundioides, F. pallidinervis, F. pauperculus, F. pellucidus, F. polypodioides, F. santa-clarensis, F. scalaris, F. serratus, F. subbasilaris, F. sublimbatus, F. submarginatus, F. taylorii, F. ventricosus, F. zollingeri
F. adianthoides, F. amoenus, F. aphelotaxifolius, F. appalachensis, F. arcticus, F. asplenioides, F. bryoides, F. bushii, F. closteri, F. crispus, F. curvatus, F. dubius, F. elegans, F. exilis, F. fontanus, F. grandifrons, F. hallianus, F. hyalinus, F. leptophyllus, F. littlei, F. minutulus, F. osmundioides, F. pallidinervis, F. pauperculus, F. pellucidus, F. polypodioides, F. santa-clarensis, F. scalaris, F. serratus, F. subbasilaris, F. sublimbatus, F. submarginatus, F. taxifolius, F. taylorii, F. ventricosus, F. zollingeri
Synonyms F. clebschii F. obtusifolius var. kansanus, F. obtusifolius var. marginatus
Name authority Hedwig: Sp. Musc. Frond., 155, plate 39, figs. 1–5. (1801) Wilson: London J. Bot. 4: 196, plate 9, fig. b. (1845)
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