Dermatosorus schoenoplecti Vánky & R.G. Shivas, Fungal Diversity

Piątek, Marcin, Lutz, Matthias, Mossebo, Dominique C. & Piątek, Jolanta, 2024, Emended description and phylogenetic placement of Dermatosorus schoenoplecti (Ustilaginales), Phytotaxa 674 (2), pp. 218-228 : 222-223

Dermatosorus schoenoplecti Vánky & R.G. Shivas, Fungal Diversity 14: 244 (2003), emend.

( Figs. 2–4 )

Type:— AUSTRALIA. Queensland: ca. 60 km SSW of Cairns, between Gordonvale and Yungaburra, 5 km turn off to “Cathedral Fig Tree”, 17°11´32˝ S, 145°39´53˝ E, alt. ca. 730 m a.s.l., on Schoenoplectiella mucronata , 28 Sept. 2001, leg. M.D. E. Shivas & K. Vánky (holotype BRIP 28979, isotype BRIP HUV 19750).

Description:— Sori in some ovaries of the inflorescences, swollen, 3–4 mm long, 1.5–2.5 mm wide, filled with spore balls, partly hidden by the scales and covered by fine whitish peridium (host epidermis) that disappears quickly during maturation releasing the spore balls. Spore balls variable in shape and size, irregular, ovoid, broadly ellipsoid, elongated, subfusiform, 220–1800 × 150–1200 µm, dark brown, opaque, composed of hundreds to thousands of lightly pigmented inner spores surrounded by a 2–3 layered cortex of darkly pigmented sterile cells. Spores pale brown to brown, in side and plane view globose, subglobose or broadly ellipsoidal, often more or less angular due to mutual pressure, 8.0–11.5 × 8.0–9.5 µm (av. ± SD, 9.8 ± 0.9 × 8.4 ± 0.4 µm, n = 40/1); wall even, 0.8–1.0 µm thick, reticulate in LM and SEM, meshes more or less polyhedral or irregular in LM and SEM, 7–12 meshes per spore diameter, interspaces tuberculate. Sterile cells dark brown, in side view flattened and collapsed on free side, in plane view globose, subglobose, ovoid or broadly ellipsoidal, usually angular or irregular (more irregular than inner spores), (8.5–)9.0–13.5 × 7.0–11.5 µm (av. ± SD, 10.7 ± 1.2 × 8.9 ± 1.2 µm, n = 40/1); wall even, 0.8–1.0 µm thick, reticulate in LM and SEM (smooth in immature sterile cells), meshes more or less polyhedral or irregular in LM and SEM, 7–10 meshes per spore diameter, interspaces tuberculate.

Specimen examined:— CAMEROON. Western Province : Department of Menoua : Bafou, ca. 6 km NE of Dschang, 05°29´06˝ N, 10°06´17˝E, elev. ca. 1492 m a.s.l., on Schoenoplectiella mucronata , 7 March 2007, leg. A. L. Njouonkou, J. Piątek, M. Piątek, C. Vánky & K. Vánky ( KRAM F-60050) ; duplicate is preserved in BRIP HUV 21460 .

Habitat: — In Africa, Dermatosorus schoenoplecti was found on the Bamiléké Plateau, which is a central part of the Cameroon Highlands, at an altitude of 1492 m a.s.l., in a swamp dominated by Rhynchospora corymbosa and Schoenoplectiella mucronata ( Fig. 2A–B ). According to White’s classification (White 1983), this part of Cameroon belongs to the Afromontane archipelago-like regional centre of endemism. The swamp was a remnant of natural vegetation surrounded by cultivated fields (banana and oil palm plantations). During the observation, at the end of the dry season, the population consisted of no more than 15 infected plants of Schoenoplectiella mucronata in the marginal part of the swamp. It is not impossible that plants growing in the central part of the swamp were also infected by the smut, but access to this site was not possible due to the high water level.

Figures

FIGURE 2. Dermatosorus schoenoplecti. A–B. General view of the habitat in Cameroon. C–D. Sori of the fungus in the ovaries of Schoenoplectiella mucronata.

FIGURE 3. Dermatosorus schoenoplecti on Schoenoplectiella mucronata by light microscopy (all from KRAM F-60050). A–B. Spore balls. C–D. Spores in median and surface view, respectively. E–F. Sterile cells. Scale bars: A–B = 500 µm, E = 50 µm, C–D, F = 10 µm.

FIGURE 4. Dermatosorus schoenoplecti on Schoenoplectiella mucronata by scanning electron microscopy (all from KRAM F-60050). A. Unbroken spore ball. B. Broken spore ball. C. Outer layer of sterile cells (and spores below them). D–E. Spores. F. Close-up of spore ornamentation. Scale bars: A–B = 100 µm, C = 20 µm, D = 10 µm, E = 5 µm, F = 3 µm.