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fissidens moss, yew-leaf pocket moss

fissidens moss, water pocket moss

Habit Plants to 11 × 3.5 mm. Plants to 120 × 6 mm.
Stem

mostly branched;

axillary hyaline nodules absent;

central strand present.

usually profusely branched;

axillary hyaline nodules absent;

central strand 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.

in numerous pairs, lanceolate to linear-lanceolate, frequently somewhat falcate, acute, to 7 × 0.6 mm;

dorsal lamina narrowed proximally, usually ending before insertion;

vaginant laminae 1/3–1/2 the leaf length, unequal, minor lamina usually rounded and free distally or narrowed and ending on or near costa;

margin ± entire, elimbate;

costa ending 15–35 cells before apex, bryoides-type;

laminal cells usually 1-stratose, sometimes 2-stratose juxtacostally, quadrate to short-oblong to hexagonal, smooth, slightly bulging, ± firm-walled, 15–23 × 10–18 µm in dorsal and ventral laminae, juxtacostal cells largest.

Seta

to 17 mm.

0.5–0.6 mm.

Sexual condition

rhizautoicous;

perigonia on short branches proximal to elongate stems;

perichaetia on short, proximal, axillary branches.

gonioautoicous and cladautoicous;

perigonia and perichaetia on short axillary branches, 1–5 per leaf axil, sometimes on elongate, axillary branches.

Capsule

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

peristome taxifolius-type;

operculum to 1 mm.

theca 0.5–0.6 mm, erect, radially symmetric;

peristome anomalous, irregularly divided, ± incomplete, often truncate, papillose;

operculum as long as seta.

Calyptra

cucullate, smooth, to 2 mm.

mitrate, smooth.

Spores

13–18 µm.

18–27 µm.

Sporophytes

1 per perichaetium.

1–5 per leaf axil, inconspicuous.

Fissidens taxifolius

Fissidens fontanus

Habitat Damp, shaded soil, humus, and rocks Attached to various substrata in stagnant and flowing water, and in coastal estuaries
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)
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from FNA
AL; AR; AZ; CA; CT; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; ME; MI; MN; MO; MS; MT; NC; NJ; NM; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; WA; WI; WV; BC; ON; Mexico; Central America; West Indies; Europe; Africa
[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.)

Fissidens fontanus and F. hallianus are aquatic species usually found in stagnant or slow moving water, but at times emergent because of fluctuating water levels (H. A. Crum and L. E. Anderson 1981; P. G. Davison and D. E. Wujek 1999). Plants of both species are usually profusely branched, delicate, and feathery in appearance with leaves often 10 times or more as long as wide. Often plants are encrusted with diatoms. Stems and leaves might also appear black due to deposition of organic matter. When dry the leaves are unusually fragile so that when being prepared for herbarium storage it is best to float plants onto sheets prior to drying.

A suite of gametophytic and sporophytic characters distinguishes Fissidens fontanus. The unequal vaginant laminae are about 1/4–1/3 the leaf length, and minor lamina is round and more or less free distally. In addition, costa ends well below the leaf apex. In fertile specimens, the clusters of 1–5 axillary, inconspicuous, dark sporophytes in each perichaetium are distinctive. The sporophytes, more prevalent than thought, are caducous and are often found in the bottom of the herbarium packets. The short seta is equal in length to that of operculum, and peristome teeth are greatly reduced, often consisting of only the truncated, undivided basal parts.

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

Source FNA vol. 27, p. 341. FNA vol. 27, p. 343.
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. 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. taxifolius, F. taylorii, F. ventricosus, F. zollingeri
Synonyms F. clebschii Skitophyllum fontanum, Octodiceras julianum var. ohioense, F. debilis, F. julianus
Name authority Hedwig: Sp. Musc. Frond., 155, plate 39, figs. 1–5. (1801) (Bachelot de la Pylaie) Steudel: Nomencl. Bot. 2: 166. (1824)
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