Fissidens microcarpus Mitt.

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 : 28-29

Fissidens microcarpus Mitt. and F. imbricatus E.Britton & E.B.Bartram

( Fig. 18)

Fissidens microcarpus is characterized by oblong, lingulate, elimbate leaves, convex laminal cells and costae ending 10-20 cells below the broadly acute leaf apices. Corticolous, rupicolous and on soil.

DISTRIBUTION. — Tropical West Africa.

Peristome

Incurved when wet, undivided to irregularly divided, 130- 170 µm long, tooth base (19.5-)23.5-45 µm wide.

The peristome of the corticolous Fissidens microcarpus differs hardly from ancestral similiretis - type. The OPL ornamentation of the undivided part is the same (compare Fig. 18A, D). The main differences are that it is irregularly divided to undivided and has shorter filaments with a papillose rather squamulose ornamentation (compare Fig. 18A, B with C).

Ornamentation

OPL trabeculae high and sharp, lamellae with a high, close ornamentation; filaments papillose with a few,indistinct squamulae.

Sporophyte

Seta 3 mm long, smooth; capsule cylindrical, 0.9 × 0.5 mm, slightly inclined, exothecial cell ± 66, the cells oblong, operculum 0. 4 mm long, spores (12.5-)14.5-20(-26.3) × 11.5- 19.5 µm, papillose.

Description and illustration

Bruggeman-Nannenga & Pursell (1990: figs 32-42).

Remarks

In Figure 18 two species are illustrated: Fissidens microcarpus with a reduced peristome ( Fig. 18 A-C) and, for comparison,

A B MABN 2021 D E C

F. imbricatus with a well-developed similiretis - type peristome ( Fig. 18C, D).