Sporisorium monocymbii (Syd.) Vánky, Mycotaxon

Denchev, Teodor T. & Denchev, Cvetomir M., 2016, Jamesdicksonia anadelphiae-trichaetae (Georgefischeriales) and Sporisorium anadelphiae-trichaetae (Ustilaginales), new species on Anadelphia trichaeta (Poaceae) from Guinea, Phytotaxa 252 (3), pp. 205-216 : 215

Sporisorium monocymbii (Syd.) Vánky, Mycotaxon 62: 145, 1997. ( Figs 45–53 )

Basionym: Sphacelotheca monocymbii Syd., Ann. Mycol. 37: 200, 1939. Synonym: Sorosporium monocymbii (Syd.) L. Ling, Sydowia 7: 155, 1953. Type: —On Monocymbium ceresiiforme (Nees) Stapf ( Poaceae ). SIERRA LEONE. Northern Province: by the road side 16 km from

Kabala on the road to Musaia, 16 November 1930, leg. F. C. Deighton 313 (holotype, IMI 43051 !; isotypes BPI 178 108, 195 108,

H.U.V. 17 481).

Sori variable, in all spikelets or groups of spikelets; all racemes of an infected plant are affected ( Fig. 45 ); initially covered by a thick, dark brown or ferrugineous brown peridium which later flakes away. At first the racemes of the infected plant are enclosed by the spatheoles ( Fig. 46 ), later more or less visible. When a group of spikelets is infected, the columella is irregularly branched ( Fig. 48 ). When individual spikelets are infected ( Fig. 47 ), the sori are 1.2–2 mm long, ovoid, with a single, stout, tapering, sometimes horn-like columella. Remnants of floral envelopes may be present between the sori. Spore mass semi-agglutinated, blackish brown, mixed with groups of sterile cells. Sterille cells in irregular groups, sometimes single or in chains, subglobose, broadly ellipsoidal or irregular, usually collapsed, 9–19(–24) μm long, usually larger than the spores, hyaline or subhyaline; wall 0.7–1.5 μm thick. In SEM smooth, sometimes partially rugulose. Spores subglobose, broadly ellipsoidal, ellipsoidal, ovoid or slightly irregular, (7–)7.5– 10.5(–11.5) × (6.5–)7–9(–9.5) (9.1 ± 0.6 × 8.1 ± 0.5) μm (n = 300), medium reddish brown; wall evenly thickened, 0.6–0.8 μm thick, minutely verruculose, spore profile slightly affected or not affected. In SEM minutely echinulate, spinules up to 0.3(–0.4) μm high, densely punctate between the spinules.

Specimen examined: — Holotype ( IMI 43051 ).

Known host and distribution: —On Poaceae : Monocymbium ceresiiforme , Africa ( Sierra Leone) (Fig. 11). Known only from the type collection ( Sydow 1939, Ling 1953, Zambettakis 1971, Vánky et al. 2011).

The seven species may be distinguished by the following key.

Figures

FIGURES 45–53. Sporisorium monocymbii on Monocymbium ceresiiforme (holotype, IMI 43051). 45–48. Habit. 46. Racema of an infected plant, enclosed by the spatheole (see the black arrow). 47. Sori in individual spikelets. 48. Sorus in a group of spikelets, with an irregularly branched columella. 49–51. Spores and sterile cells in LM (in median view—Figs 49, 50, in surface view—Fig. 51). Black arrow shows sterile cells. 52. Spores in SEM. 53. Spores and sterile cells in SEM. Scale bars: 45 = 1 cm, 46–48 = 0.5 cm, 49–51 = 10 μm, 52, 53 = 5 μm.