Fissidens fontanus
Fissidens submarginatus
fissidens moss, water pocket moss
usually profusely branched;
axillary hyaline nodules absent;
central strand absent.
unbranched and branched;
axillary hyaline nodules absent;
central strand weak.
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 10 pairs, lanceolate to lingulate, acute to obtuse-apiculate, to 1.3 × 0.4 mm;
dorsal lamina narrowed abruptly proximally, ending at insertion, not decurrent;
vaginant laminae ± 1/2 leaf length, equal;
margin serrulate, limbate and entire on complete length of vaginant laminae and often on proximal portion of adjacent ventral laminae of all leaves except smallest, limbidial cells 1-stratose;
costa percurrent to ending 2–3 cells before apex, bryoides-type;
laminal cells 1-stratose, distinct, mammillose, firm-walled, quadrate to hexagonal, 7–9 µm. Sexual condition rhizautoicous;
perigonia gemmiform, proximal to fertile and infertile stems.
0.5–0.6 mm.
to 3.5 mm.
gonioautoicous and cladautoicous;
perigonia and perichaetia on short axillary branches, 1–5 per leaf axil, sometimes on elongate, axillary branches.
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 0.6 mm;
peristome scariosus-type;
operculum to 9.4 mm.
mitrate, smooth.
cucullate, smooth, to 0.5 mm.
18–27 µm.
11–23 µm.
1–5 per leaf axil, inconspicuous.
1 per perichaetium.
Fissidens fontanus
Fissidens submarginatus
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 submarginatus is most likely to be confused with F. leptophyllus. Both species have mammillose laminal cells, serrulate leaf margin, and limbidium of 1-stratose cells restricted essentially to vaginant laminae. The limbidium is the best character by which these two species are separated. In F. submarginatus the limbidium consistently extends the entire length of the vaginant laminae of most or all leaves, and on occasion extends a short distance onto the proximal part of the adjacent ventral lamina. In contrast, the limbidium in F. leptophyllus consistently extends no more than 1/2 the length of the vaginant laminae of most leaves. Minor differences can also be found in the shape of the leaf apex (usually apiculate vs. not apiculate), costa length (ending 2–3 cells before the leaf apex vs. ending 2–6 cells before the leaf apex), and cell size (7–9 µm versus 7–12 µm).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC - Local Web sites:
CalFlora, CalPhotos, 
Flora NW, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
