Hypoxylon annulatum (Schwein.: Fr.) Mont.

TELEOMORPH | CULTURES AND ANAMORPH | SPECIMENS EXAMINED | NOTES

NOTES

Both H. annulatum and H. truncatum are highly associated with Quercus species. Hypoxylon annulatum differs from H. truncatum in having consistently massive hemispherical stromata, in having unpronounced perithecial mounds, in having a faint, convex ostiolar disc, in having an olivaceous stromatal surface, and in not having conidiophores with a long robust melanized main axis when found on natural substrate. Their conidiophores, when found in culture, are very similar. Hypoxylon annulatum and H. truncatum were considered to be conspecific by Miller (1961). Interestingly, Yoon and Glawe (1993) did a molecular-based study of H. truncatum sensu J. H. Miller and concluded that H. annulatum and H. truncatum are distinct species.

Shear (1945) proposed to apply H. annulatum and H. marginatum to specimens of what we consider to be H. truncatum and H. annulatum, respectively. This is not feasible for the following two reasons. First, while publishing Sphaeria marginata Schwein., Schweinitz (1832) referred it back to his 1825 paper where one finds S. annulata Schwein. Obviously, Schweinitz used S. marginata as a substitute for S. annulata, as stated by Shear (1945). This indicates that these two names are nomenclatural synonyms; accordingly, S. marginata Schwein. is nomenclaturally superfluous, and should be rejected under ICBN Art. 63.1. Secondly, Sphaeria marginata Schwein. is predated by two homonyms: S. marginata Fr.: Fr. [º Biscogniauxia marginata (Fr.: Fr.) Pouzar] and S. marginata Sowerby which, according to Fries (1828), is S. leucostoma Pers.: Fr. [º Leucostoma persoonii Höhn.]. Under ICBN Art. 64.1, Sphaeria marginata Schwein. should be likewise rejected. Among those specimens sent to him by Schweinitz, Fries (1828) erected a new taxon, S. annulata var. depressa Fr.: Fr., with stromata "irregulariter effusa,..., purpurascenti-nigra" in contrast to Schweinitz's typical variety with stromata, in Fries' words, "hemisphaerica, confluens, nigricans". There is no specimen labeled as S. annulata var. depressa at UPS. The type material of S. annulata Schwein.: Fr. at UPS contains four pieces, and these are shown in a photograph in Shear (1945). Two pieces which were marked as "A" by Starback on the paper card are H. annulatum. The piece corresponding to the part marked as "Y" in Fig. 3 in Shear (1945) does not have any fungal component. The piece corresponding to the part marked as "X" in Fig. 3 in Shear (1945) is H. truncatum. It is probable that Fries' S. annulata var. depressa was based on the H. truncatum element; we thus select this element as the lectotype of S. annulata var. depressa Fr.: Fr., and consider it to be a synonym of H. truncatum.

At PH, three packets of Schweinitz's autographed material corresponding to our interpretation of H. annulatum were labeled by Schweinitz as follows: Sphaeria annulata [Collins Coll. no. 18] which is selected as the lectotype, S. multiformis var. annulata [Syn. 1173], and S. marginata [Syn. 1176]. In the last packet [Syn. 1176], one can even find additional evidence that Schweinitz intended to replace S. annulata with S. marginata: Sphaeria annulata was crossed out and S. marginata was written over it.

We did not locate the type of H. marginatum var. emarginata Theiss. Miller's interpretation of this name (Miller, 1961, Fig. 163) is H. annulatum.