Fissidens crispus
Fissidens grandifrons
largeleaf fissidens moss
unbranched and branched;
axillary hyaline nodules absent;
central strand present or absent.
usually profusely branched;
axillary hyaline nodules present;
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 as many as 60 or more pairs, lanceolate, obtuse to rounded, to 3 × 0.5 mm;
dorsal lamina narrowed proximally, ending at insertion;
vaginant laminae 1/2–2/3 leaf length, acute, equal;
margin ± entire to crenulate, elimbate;
costa usually difficult to discern, ending a few cells before apex, variable in structure, basically taxifolius-type;
lamina cells 1- to 4-stratose at leaf margin, 2- to pluristratose in interior of dorsal and ventral laminae, 1- to 4-stratose in vaginant laminae, smooth, ± plain, quadrate to hexagonal, 7–13 µm long.
to 9 mm.
13–19 mm.
gonioautoicous and rhizautoicous.
dioicous (?);
perigonia not seen;
perichaetia on short axillary branches in medial leaves.
theca exserted, inclined, bilaterally symmetric to erect, radially symmetric, to 1 mm;
peristome bryoides-type;
operculum 0.5 mm.
theca slightly arcuate, bilaterally symmetric, astomatose, exothecial cells quadrate to oblong, vertical walls thicker than horizontal walls, 1.5–2 mm;
peristome taxifolius-type.
cucullate, smooth, 0.8 mm.
10–16 µm.
20–23 µm.
1–2 per perichaetium.
Fissidens crispus
Fissidens grandifrons
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 grandifrons is the only species in the flora area with pluristratose laminal cells. It is a robust aquatic species, usually coarse to the touch. The plants are often brown-black, the result of deposition of organic matter. Reproduction in North America, where sporophytes have never been found, is by vegetative means. According to E. J. Hill (1902), multiplication is by small, radiculose branches that are easily detached in the rapidly running streams. Although the gametophyte of F. grandifrons is specialized to an aquatic habitat (thick, lanceolate leaves and long archegonia; Z. Iwatsuki and T. Suzuki 1982; R. A. Pursell and B. H. Allen 1994), the species has retained a distinctly terrestrial type of sporophyte. The description of the sporophyte given here is based on three specimens: Lai 8699 (NY) and Lin 12831 (NICH) from Taiwan; and Higuchi 20161 (NICH) from Pakistan. A. J. Grout (1943) stated that the operculum is “conic-rostrate, about 1 mm long,” and Iwatsuki and Suzuki reported that the calyptra is “cucullate, about 1.6 mm long, smooth.”
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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