The genus Polystigma was erected by Persoon in 1812 for a sample 170 of the exsiccata collection "Stirpes Cryptogamae Vogeso-Rhenanae quas in Rheni superioris ingeriorisque nec non Vogesorum praefectiers collegerunt" by Mougeot and Nestle. Cannon, in his monography of the genus, write that this names was illegittime under the art. 32 of ICBN: "The name Polysfigma was apparently first introduced by Persoon on an exsiccatum label in 1812, but no description of the genus was provided. The name was validated three years later by de Candolle (in Lamarck & de Candolle, 1815)" (Cannon, 1996: 1416). (for the art. 32 of ICBN see: http://ibot.sav.sk/icbn/frameset/0036Ch4Sec2a032.htm; see ex. 2)

In PI I found a copy of this sample. The label say: "270. Polystigma rubrum Perso. in Litteris. Xyloma rubrum Pers. Syn. Fung. p. 105. In foliis Pruni domesticae et spinosae, Autumno". The label has no description of the genre but have a reference to a previously and effectively published description or diagnosis: that of Xyloma rubrum Pers. (see: art. 32.1 point D)

In conclusion: the name Polystigma rubrum is valid as Persoon in Mougeot & Nestle, Stirpes Cryptogamae Vogeso-Rhenanae: n. 270. 1812 or as De Candolle, Flore française ed. 3, 6: 164. 1815 ?


PS: sorry for me English...