Milesina exigua Faull, Contributions from the Arnold Arboretum of Harvard University 12: 218‒219 (1931)

Bubner, Ben, Buchheit, Ramona, Friedrich, Frank, Kummer, Volker & Scholler, Markus, 2019, Species identification of European forest pathogens of the genus Milesina (Pucciniales) using urediniospore morphology and molecular barcoding including M. woodwardiana sp. nov., MycoKeys 48, pp. 1-40 : 1

Milesina exigua Faull, Contributions from the Arnold Arboretum of Harvard University 12: 218‒219 (1931) Figure 6d, e

Polystichum aculeatum (L.) Roth ( P. lobatum L., Aspidium lobatum Sw.). Ukraine, Kolomyja: Knyazhdvir, Aug 1913, A. Wróblewski (as M. vogesiaca : Sydow, Uredineen 2742; GLM, GLM-53030; W, 1916-4289); Knyazhdvir, Sep 1913, A. Wróblewski (as M. vogesiaca : W, 1975-18645).

Polystichum braunii (Spenn.) Fée. Austria, Steiermark: Buchgraben NE Oberschöckl, canyon slope, 26 Apr 1983, J. Poelt, (GZU, GZU 000313869; M, M-0205472); Deutschlandsberg, Freiland, Wildbachklamm, south of the stream, scarp, 31 Jul 2018, M. Scholler & C. Scheuer (KR, KR-M-0050247); Höllgraben, ravine forest, 29 Sep 1988, J. Poelt & P. Zwetko (M, M-0205473). Koralpe, Mausegger-Graben next Sauerbrunn, NW Stainz, district Deutschlandsberg, ravine forest, silicate rock, 17 Apr 1995, J. Poelt (GZU, GZU 000313870); NW Stainz, Höllgraben WNW Marhof, ravine forest, 29 Sep 1988, J. Poelt & P. Zwetko (GZU, GZU 000313867).

Description.

Urediniospores hyaline, ellipsoidal to obovoidal, clavate, 22.5-32.5 × 12.5-17.5 µm, mostly 22.5-30.0 × 12.5-17.5 µm; wall 0.5-0.8 µm; spores smooth, germ pores low in number, probably around 4-6, 2.0-3.8 µm, mostly 2.0-3.0 µm diam., Ø 2.7 µm diam.; germ pores mostly apically, or both, basally and apically (bizonate).

Comment.

Klenke and Scholler (2015: 649) list this species (as M. neoexigua Berndt) on Polystichum braunii for Germany ( Baden-Württemberg), based on a specimen from the Black Forest, SW Germany (KR-M-0019138). P. braunii is a rare member of the southern Black Forest flora. We revised host and fungus and found that it is M. vogesiaca on P. aculeatum . Thus, the presence of M. exigua in Germany has not been confirmed. Germ pores are more difficult to visualise and need more time to evaluate.