Fissidens papillisetus 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 : 23-27

Fissidens papillisetus Brugg. -Nann.

( Fig. 13 )

Fissidens papillisetus is characterized by lanceolate, acute to slightly acute-acuminate leaves, margins of vaginant laminae plane, laminal cells mammillose, limbidia as a rule well developed, intramarginal, setae and calyptrae strongly papillose and peristomes with undivided teeth, basal OPL lamellae with numerous, thin, high, close ridges and filaments spirally ornamented. It resembles F. pocsii sensu lato. The two differ in the relative width of leaves, those of F. papillisetus are 4-5 times as long as wide, those of F. pocsii are mostly wider, in the margins of the vaginant laminae which are typically revolute in F. pocsii and plane in F. papillisetus and in the ornamentation of the basal OPL lamellae. In F. papillisetus this ornamentation consists of many close-packed, high, thin plates ( Fig. 13B, C ) and trabeculae hard to observe, whereas in F. pocsii the basal OPL trabeculae are distinct and the lamellar ornamentation is spaced and lower ( Fig. 14A, D). The two species further have a different geographic distribution. Corticolous on branches.

DISTRIBUTION. — Endemic to Mauritius.

Peristome

Just above the insertion genu-flexed, undivided, ±100 µm long (hard to measure), tooth base 25-33 µm wide.

Ornamentation

Basal OPL lamellae with thin, close-packed, high, striate plates ( Fig. 13E ) that are not or hardly distinguishable from the trabeculae ( Fig. 13B, C ); IPL with firm, close, horizontal to oblique ridges over almost the complete length ( Fig. 13D ); filaments “annular-spiral”, becoming papillose near the apex.

Sporophyte

Seta 1.2-1.6 mm long, strongly papillose; capsule narrowly cylindrical, 0.5-0.65 × 0.2-0.25 mm, exothecial cell columns ± 32 columns, the cells linear-oblong; operculum short rostrate, 0.2-0.25 mm long; spores 16.0-25.5 µm, smooth.

Description and illustration

Bruggeman-Nannenga (in press: 40; fig. 3).

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.