Fissidens pocsii Bizot & Dury ex Pócs

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

Fissidens pocsii Bizot & Dury ex Pócs sensu lato

( Fig. 14)

Fissidens pocsii sensu lato is characterized by mammillose laminal cells, vaginant laminae with revolute margins, limbidia present on some or all leaves of perichaetial stems, leaves of vegetative stems limbate or not, antheridia in axillary buds as well as terminal, setae short, papillose. It is a rather heterogeneous species. It appeared, however, impossible to find differentiating features for its expressions. Differences in leaf shape, length of the costa, in anatomy of the stem, peristomes divided or undivided, growing on twigs or on bark of trees or large branches and geographical distribution appeared to be weakly or not correlated. Cross-sections of stems in this complex vary from round to elliptical, central strand present or not and walls of inner cells strongly incrassate ( Fig. 14C) or thin. Corticolous on trees and twigs (Malagasy species on twigs).

DISTRIBUTION. — Tanzania, La Réunion and Madagascar.

Peristome

The peristome of this species is too variable to allow a description that is comparable to the other descriptions and does do justice to its variability. In Figure 14 a divided and an undivided peristome are shown. Peristomes of this species have “spiral” filaments. The peristome can be divided or not and the ornamentation of the basal OPL is variable. On the IPL the “spiral” ornamentation is not limited to the filaments but, like in Fissidens papillisetus , continues almost to the insertion (this feature, however, could not be checked in all specimens because of the poor quality of some peristomes). When undivided the peristome resembles that of F. papillisetus from which it differs by the OPL lamellae of the basal part: in F. papillisetus the lamellae are close packed ( Fig. 13B, C ) and in F. pocsii not ( Fig. 14A, D). For further differences see F. papillisetus . When divided the peristome resembles that of F. inclusus . In F. inclusus , however, the IPL lamellae of the undivided part are smooth or have an inconspicuous ornamentation ( Fig. 9C ) whereas in F. pocsii there is a prominent ornamentation similar to that of the of the filaments ( Fig. 14E). Furthermore, F. inclusus has shorter setae and limbidia that are restricted to the vaginant laminae of the upper perichaetial leaves.

Illustration and description

Bruggeman-Nannenga & Arts (2010: fig. 28).

Figures

FIG. 13. — Fissidens papillisetus Brugg.-Nann. A, capsule with operculum; B, OPL of two teeth with spore; C, genuflexed basal part of tooth in side-view showing the high, close lamellar ornamentation; D, IPL of two teeth; E, detail of lamellar OPL ornamentation showing three free laying plates of which two with vertical striae on the right remnants of the operculum; F, “spiral” ornamentation of filaments; G, scabrose calyptra; H, papillose seta. All from Mauritius, Mt. Le Pouce, Florins & Pócs 9538/B, holotype: private herbarium Bruggeman-Nannenga, isotype: EGR. Scale bars: A, G1, 0.5 mm; B-F, 20 µm; G, 100 µm; H, 50 µm.

FIG. 9. — Fissidens inclusus Bizot & Dury ex Pócs. A, capsule mouth with peristome. Four teeth on the left and three on the right seen from the OPL-side, in the mid IPL of pair of teeth; B, OPL of undivided part and bifurcation; C, IPL basal part and basal filaments plus spore;D, IPL distal filaments; E, capsule (moist) with straight erect teeth. All from holotype, Tanzania, Nguru Mts, on the ridge S of Kwamanga Village above Mhonda mission nr Turiani, Pócs & Mabberley 6398/A, EGR. Scale bars: A, 50 µm; B-D, 20 µm; E, 0.5 mm.