Hypoxylon ferrugineum Otth

We so far did not collect H. ferrugineum in Pyrénées and therefore we cannot illustrate it properly.

It has been described by Petrini & Müller (1986) and Ju & Rogers (1996), and characterized by erumpent, pulvinate, dark brick (60) stromata with orange KOH-extractable pigments and ascospores 14-17 x 6.5-8 µm, and host specificity for Tilia. In a recent report from Austria by Scheur et al. (2001), ascospores of H. ferrugineum are given 12.5-15.5 (-17.5) x 5.5-9.5 µm.

Results of HPLC analyses show that H. ferrugineum belongs to the H. fragiforme chemotype, with mitorubrin, mitorubrinol and orsellinic acid, and lack of BNT and rubiginosins (Stadler et al., 2004b). The HPLC profiles from material from Switzerland on Sorbus aucuparia and Tilia (Stadler et al., 2004b) are identical to those from material from Canada on Populus (Stadler, pers. comm.) in showing a characteristic peak corresponding to an unknown compound. These data prove H. ferrugineum is well characterized and less host specific than previously assumed. It was so far reported from Austria, Switzerland and northern North America (Petrini & Müller, 1986; Ju & Rogers, 1996; Scheur et al., 2001), suggesting an alpine distribution.