Fissidens pseudoplumosus Bizot & Onr. ex Brugg.

Bruggeman-Nannenga, Maria Alida, 2022, On the peristomes of the corticolous African species of Fissidens Hedw. (Fissidentaceae, Bryophyta), Cryptogamie, Bryologie 20 (2), pp. 9-36 : 27-28

Fissidens pseudoplumosus Bizot & Onr. ex Brugg. -Nann.

( Fig. 15 )

Fissidens pseudoplumosus is characterized by distant, scale-like leaves on the basal halves of the stems and linear-oblong to linear-lanceolate acute leaves on the upper halves, irregularly bistratose dorsal and apical laminae and limbidia restricted to the basal half of the vaginant laminae of upper and middle leaves of perichaetial plants. Fissidens pseudoplumosus has two subspecies. These have similar gametophytes and peristomes but differ in length of the setae and geographical distribution. Fissidens pseudoplumosus subsp. pseudoplumosus has very short 0.5 mm long setae and thus immersed capsules. It is known from Réunion where it grows on tree ferns and once collected from organic debris originating from a tree fern. Subspecies subplanifrons has longer, 1-2 mm long, setae and emergent to exserted capsules. It is known from Mauritius, Madagascar and the Comoro Islands Mwali and Ndzuani and also grows on tree ferns.

Peristome

±erect when wet, variable, irregularly divided or seemingly perforated, some teeth narrowing abruptly into a single filament, 120-250 µm long (hard to measure, often broken off), tooth base 32-38 µm wide.

Ornamentation

OPL basal 7-8 cells undivided, trabeculae smooth, papillose, well developed; proximal cells of the filaments with prominent, reticulate lamellar ornamentation ( Fig. 15D, H ); IPL basal undivided part with papillose trabeculae and smooth lamellae; lamellae of filaments thick plates ( Fig. 15E ); with high, close horizontal to oblique ridges ( Fig. 15F ), filaments “hemispiral” with close, oblique ridges present on the IPL but not on the OPL, apical part densely papillose on both layers. Characteristic of this peristome are irregularly divided teeth, relatively tall undivided parts and “hemispiral” filaments.

Sporophyte

Seta 0.5 mm in Fissidens pseudoplumosus pseudoplumosus and 1-2 mm in Fissidens pseudoplumosus subplanifrons (Bizot & Onr. ex Brugg.-Nann.) Brugg.-Nann. & Arts; capsule narrowly cylindrical, 0.7-0.9 × 0.3-0.4 mm, exothecial cell columns ±32, the cells oblong; operculum unknown; spores 13-20 µm, ± smooth.

Description and illustration

For subsp. pseudoplumosus : Bruggeman-Nannenga & Arts (2010: fig. 30); for subsp. planifrons : ( Bizot 1974: pl. 4); Bruggeman-Nannenga & Arts (2010: fig. 31).

Figures

FIG. 15. — Fissidens pseudoplumosus Bizot & Onr. ex Pócs subsp. pseudoplumosus: A-C, G. A, OPL basal part and bifurcation; B, C, basal IPL, showing papillose trabeculae and smooth lamellae;G, papillose distal filaments. F. pseudoplumosus subsp.subplanifrons (Bizot & Onr.ex Brugg.-Nann.) Brugg.-Nann. & Arts: D-F, H-I. D, focused on the irregular somewhat reticulate OPL ornamentation;E, same tooth as Fig. D, but focused deeper to show the incrassate lamellar plates; F, side view basal part of tooth, OPL on the right; H, basal part of filament focus on OPL ornamentation; I, same tooth as Fig. H, focused on the “hemispiral” IPL ornamentation of high, dense oblique ridges. A, B, G from La Réunion, La Grande Montagne, Route Forestière de la Plaine d’Affouche, Arts REU122-38, BR, private herbarium M.A. Bruggeman-Nannenga; C from La Réunion, eastern slope of Piton de la Fournaise, sentier de la Ravine du Tremblet, Onraedt 9378, PC, type of F.pseudoplumosus; D-F, H-I from Mauritius,Shoulder of the Ponce (subsp.subplanifrons), Ayres s.n., type of subsp.subplanifrons, BM. Scale bar: 20 µm.