Fissidens scalaris
Fissidens grandifrons
largeleaf fissidens moss
unbranched and branched;
axillary hyaline nodules present;
central strand present.
usually profusely branched;
axillary hyaline nodules present;
central strand absent.
as many as 16 pairs, oblong to lanceolate, acute to short-acuminate, to 1.3 × 0.25 mm;
dorsal lamina narrowed proximally, ending well above or at insertion;
vaginant laminae ± 4/5 leaf length, ± equal, minor lamina ending on or near margin;
margin ± entire to crenulate-serrulate, limbate on all laminae, limbidium variable, developed best on vaginant laminae, ceasing well before apex, limbidium cells 1-stratose;
costa ending 2–5 cells before apex to percurrent, bryoides-type;
laminal cells 1-stratose, distinct, smooth, somewhat bulging, firm-walled, irregularly quadrate to hexagonal, 9–14 µm, increasing somewhat in size and ± oblong in proximal parts of vaginant laminae.
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.
2–6 mm.
13–19 mm.
rhizautoicous;
perigonia gemmiform, proximal to fertile and infertile stems, and as branches along horizontal parts of stems.
dioicous (?);
perigonia not seen;
perichaetia on short axillary branches in medial leaves.
theca exserted, erect, radially symmetric, 0.5–1.25 mm;
peristome anomalous, variable, even in same theca, teeth undivided, imperfectly divided or divided 4/5 their length, papillose distally, smooth proximally;
operculum 0.22–0.3 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, to 0.45 mm.
20–26 µm.
20–23 µm.
1 per perichaetium.
Fissidens scalaris
Fissidens grandifrons
Fissidens scalaris, although widespread in the southern part of the United States, is infrequently collected. It is best distinguished by its dimorphic stems and undivided to deeply divided, papillose peristome teeth. B. E. Lemmon (1965) published photographs of the development of plants, including perigonial, perichaetial, and infertile stems, and peristome.
(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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