Fissidens fontanus
Fissidens bryoides
fissidens moss, water pocket moss
bryoid fissidens moss, lesser pocket-moss
usually profusely branched;
axillary hyaline nodules absent;
central strand absent.
unbranched and branched;
axillary hyaline nodules absent;
central strand usually present.
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.
as many as 20 pairs, lanceolate to oblong-lanceolate or oblong-lingulate, acute to short-acuminate or obtuse-apiculate, to 0.8–2.7 × 0.2–0.5 mm;
dorsal lamina narrowed proximally, ending at or before insertion, infrequently slightly decurrent;
vaginant laminae 1/2 leaf length, mostly equal;
margin entire but often serrulate distally, limbate on all laminae, limbidium reaching apex or ending a few cells before or partially absent to infrequently completely absent, limbidial cells 1–3-stratose;
costa excurrent to ending as many as 6 cells before apex, bryoides-type;
laminal cells 1-stratose, distinct, smooth, often slightly bulging, firm-walled, irregularly hexagonal, a few elongate, 6.5–16 µm, somewhat larger in proximal parts of vaginant laminae.
0.5–0.6 mm.
1.4–10 mm.
gonioautoicous and cladautoicous;
perigonia and perichaetia on short axillary branches, 1–5 per leaf axil, sometimes on elongate, axillary branches.
polyoicous;
naked antheridia and archegonia often in axils of distal leaves.
theca 0.5–0.6 mm, erect, radially symmetric;
peristome anomalous, irregularly divided, ± incomplete, often truncate, papillose;
operculum as long as seta.
theca exserted, erect, radially symmetric to ± inclined, bilaterally symmetic, 0.2–1.2 mm;
peristome bryoides-type;
operculum 0.5 mm.
mitrate, smooth.
cucullate smooth, to 0.5 mm.
18–27 µm.
10–20 µm.
1–5 per leaf axil, inconspicuous.
1–2 per perichaetium.
Fissidens fontanus
Fissidens bryoides
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.)
Fissidens bryoides is a veritable kaleidoscope of intergrading expressions. At one extreme is F. bryoides in the strict sense, with plants gonioautoicous and the limbidium, 1–3 cells thick, confluent at the leaf apex with the percurrent to short-excurrent costa. At the other extreme is the expression that has been singled out as F. exiguus, with plants rhizautoicous and the 1-stratose limbidium usually restricted to the vaginant laminae of perichaetial leaves. In rare cases the limbidium can be absent from all leaves. All expressions, however, have clear, distinct, 1-stratose, irregularly hexagonal laminal cells, 6.5–16 µm, that in transverse section are no deeper than wide, and that have smooth walls that can be slightly bulging. H. A. Crum and L. E. Anderson (1981) illustrated the major expressions found in the flora area. Axillary, multicellular gemmae have been reported in Indian specimens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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