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Page number:24 
Remarks (internal):The typical darker, equatorial band is present in mature spores only. Ustilago planetella differs from Ustilago spermophora [= Macalpinomyces spermophorus] by the lack of a caryopsis remnant on the top of the sori, by mature spores with a typical, dark equatorial band and two, paler, thin-walled polar areas, and absence of sterile cells. In M. spermophorus has usually a hard, yellowish-brown, acute body on the top of the sori spores that are uniformly pigmented, lacking paler polar areas, and sterile cells between the spores. The ITS 1 and ITS 2 regions of the rDNA including the 5.8S rDNA (ITS) and the 5´-end of the nuclear large subunit ribosomal DNA (LSU) of Ustilago planetella were sequenced by Dr. M. Lutz. [GenBank accession numbers: EF040584 (ITS), EF040583 (LSU)]. Molecular phylogenetic analyses using the dataset of Stoll et al. (2005) revealed a position within Ustilago s.l. in a cluster together with U. calamagrostidis, U. cynodontis, U. sparsa, U. striiformis, and U. xerochloae.
 
Description type:Original description 
Description:Ustilago planetella Vánky & R.G. Shivas, sp. nov.
MycoBank510364.
Sori (Fig. 3) in some spikelets of an inflorescence destroying the innermost floral organs, inconspicuous, globose, ovoid or broadly ellipsoidal, 0.2-0.5 x 0.2-0.6 mm, more or less hidden by the glumes, at first covered by a thin, greyish peridium which ruptures irregularly at maturity disclosing the dark brown, powdery mass of spores. Spores (Figs. 8, 9) slightly compressed or not, in side view circular to elliptic, 7-10 µm wide, with two, thin-walled, subhyaline polar areas and a wide, darker equatorial band, in face view spores circular, subcircular or broadly elliptic, 8-10.5 x 9-12 µm, pale yellowish-brown with a round, paler, central spot, 3-5 µm in diam., corresponding to the polar area; spore wall uneven, c. 1 µm thick at the darker, equatorial band, and c. 0.5 µm at the polar areas, surface apparently smooth to finely, sparsely to moderately densely punctate-verruculose, spore profile smooth to finely wavy at the polar areas. Sterile cells not seen.
On Eragrostis japonica (Thunb.) Trin.; S.E. Asia (Thailand). Known only from the type locality.
Etymology: The specific epithet refers to the smut genus Planetella Savile, with its type P. lironis Savile, on Carex spp., in which the spores also have a dark, equatorial band and two, paler polar areas. It is important to note that the immature spores are uniformly pale yellowish-brown pigmented, thin-walled.
 
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