Fissidens crispus
Fissidens fontanus
fissidens moss, water pocket moss
unbranched and branched;
axillary hyaline nodules absent;
central strand present or absent.
usually profusely branched;
axillary hyaline nodules absent;
central strand absent.
as many as 20 pairs, elliptic to broadly lanceolate to oblong-lingulate, acute, short-acuminate to obtuse-apiculate, to 2 × 0.5 mm;
dorsal lamina narrowed proximally, ending before insertion to ± decurrent;
vaginant laminae 2/3–3/4 leaf length, equal;
margin ± entire but usually serrulate distally, limbate on all laminae, limbidium usually ending a few cells before apex, frequently edged by 1–2 rows of quadrate to oblong chlorophyllose cells in proximal parts of vaginant laminae, limbidial cells 1–2-stratose;
costa percurrent to ending 2–5 cells before leaf, infrequently short-excurrent, bryoides-type;
laminal cells 1-stratose, smooth, strongly bulging, densely chlorophyllose, ± obscure, firm-walled, irregularly quadrate to hexagonal, usually arranged in discernable rows in distal part of leaf, 6–10 µm, twice as deep as wide.
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.
to 9 mm.
0.5–0.6 mm.
gonioautoicous and rhizautoicous.
gonioautoicous and cladautoicous;
perigonia and perichaetia on short axillary branches, 1–5 per leaf axil, sometimes on elongate, axillary branches.
theca exserted, inclined, bilaterally symmetric to erect, radially symmetric, to 1 mm;
peristome bryoides-type;
operculum 0.5 mm.
theca 0.5–0.6 mm, erect, radially symmetric;
peristome anomalous, irregularly divided, ± incomplete, often truncate, papillose;
operculum as long as seta.
cucullate, smooth, 0.8 mm.
mitrate, smooth.
10–16 µm.
18–27 µm.
1–2 per perichaetium.
1–5 per leaf axil, inconspicuous.
Fissidens crispus
Fissidens fontanus
Three species belong to the Fissidens crispus complex; F. crispus, F. minutulus, and F. sublimbatus. A well-developed limbidium and small (6–10 µm), bulging, obscure laminal cells that in transverse section are twice as deep as wide characterize all three.
Fissidens crispus, better known in western North America as F. limbatus, is highly variable and widespread, ranging widely in tropical America, where it also attains its greatest variability. It is best distinguished by laminal cells that are usually arranged in discernable rows in the distal parts of leaves. The dorsal lamina is quite variable, ending above the insertion to long-decurrent as in some tropical expressions. Leaves, when dry, are usually crispate. The limbidium is found on all or most leaves and usually extends to or ends just before the apex.
(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.)
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