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fissidens moss, pygmy pocket moss, slender pocket-moss

Habit Plants 1.2–10 × 1–2.5 mm. Plants to 2.5 × 2 mm.
Stem

unbranched and branched;

axillary hyaline nodules present;

central strand weak or absent.

unbranched;

axillary hyaline nodules absent;

central strand absent.

Leaves

as many as 25 pairs, narrowly lanceolate to ovate–lanceolate, acute to sharply acute to short acuminate, to 1.9 × 0.3;

dorsal lamina narrowed proximally, ending before or at insertion, infrequently ± decurrent;

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

margin entire, limbate on all laminae, limbidium confluent at apex or ending shortly before apex, extending to base of dorsal lamina, limbidial cells 2–3-stratose;

costa percurrent to excurrent, bryoides-type;

laminal cells 1-stratose, distinct, smooth, ± bulging, firm-walled, elongate, 7–22 × 4–13 µm, increasing in size toward proximal part of leaf.

as many as 4 pairs, lanceolate to oblong-lanceolate, acute to obtuse-apiculate, to 2.1 × 0.4 mm;

dorsal lamina ending before insertion;

vaginant laminae 2/5 leaf length, unequal, minor lamina narrowed, ending on or near costa;

margin of dorsal and ventral laminae ± entire to crenate-serrulate, crenate-dentate on vaginant laminae, elimbate;

costa percurrent to ending 2–3 cells before apex, bryoides-type;

laminal cells distinct, smooth, plane, firm-walled, irregularly quadrate to irregularly hexagonal, 10–15 µm, marginal cells slightly smaller, vaginant laminal cells somewhat larger with 2–3 intralaminal rows irregularly elongate.

Seta

to 12 mm.

2–9 mm.

Sexual condition

rhizoautoicous;

perigonia gemmiform, proximal to infertile and fertile stems.

rhizautoicous;

perigonia gemmiform, proximal to perichaetial stems or scattered over protonemata.

Capsule

theca exserted, ± erect, radially symmetric to inclined, arcuate, bilaterally symmetic, 0.35–1.25 mm;

peristome bryoides-type;

operculum 0.25–0.3 µm.

theca exserted, erect, radially symmetric, infrequently slightly arcuate, bilaterally symmetric, to 0.7 mm;

operculum 0.4–0.6 mm;

peristome scariosus-type.

Calyptra

cucullate, smooth, 0.5 mm.

cucullate, smooth, 0.5 mm.

Spores

11–18 µm.

11–14 µm.

Sporophytes

1 per perichaetium.

1 per perichaetium.

Fissidens curvatus

Fissidens exilis

Habitat Bare, shaded soil, often among grasses in open Quercus forests and around bases of coastal shrubs Bare, damp soil of shaded banks and in seepage areas
Distribution
from FNA
CA; Mexico; South America; West Indies; Europe; Asia; Africa; Pacific Islands (New Caledonia, New Zealand); Australia
from FNA
AL; IL; IN; KY; MD; ME; MI; MO; NC; NJ; NY; OH; PA; TN; VT; QC; Europe; Asia; Africa [Introduced in North America; also introduced in West Indies]
Discussion

Fissidens curvatus is distinguished by its delicate dimorphic stems, usually long excurrent costa, limbidium confluent at leaf apex, and slightly elongate laminal cells. The theca is usually arcuate but can also be erect.

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

Fissidens exilis, first reported for North America by W. C. Steere (1950), is probably inadvertently introduced from Europe. It can be distinguished from all other tiny Fissidens in the flora area by the 2–3 rows of irregularly elongate intralaminal cells in the vaginant laminae. Plants of this species would be easily passed over were it not for the persistent protonemata that often form dark green velvetlike carpets over the substrate and the numerous sporophytes that are produced. The gemmiform perigonia are often seen scattered over the protonemata. B. H. Allen et al. (2004) have reviewed and mapped the distribution of F. exilis in North America.

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

Source FNA vol. 27, p. 347. FNA vol. 27, p. 355.
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. 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. taxifolius, 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. 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. taxifolius, F. taylorii, F. ventricosus, F. zollingeri
Synonyms F. milobakeri
Name authority Hornschuch: Linnaea 15: 148. (1841) Hedwig: Sp. Musc. Frond., 152, plate 38, figs. 7–19. (1801)
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