Introduction to Kretzschmaria Fr.



Kretzschmaria Fr. was recently reinstated by Rogers and Ju (1998) to accommodate xylariaceous fungi closely related to Nemania S. F. Gray  and effused forms of Xylaria Hill ex Schrank with regard to developmental morphology and anamorphic characters. Rogers and Ju (1998) listed in detail the distinctive characters of Kretzschmaria and we refer the reader to their work for a comprehensive definition of this genus.

Kretzschmaria is mostly represented in tropical regions, 16 taxa are accepted by Rogers and Ju (1998), of which only one is distributed in temperate regions, K. deusta (Hoffm.: Fr.) P. Martin. Kretzschmaria deusta has formerly been placed in various genera, among which Ustulina Tul.& C. Tul. has long been retained by most of authors, until Miller (1961) placed it within his broad concept of Hypoxylon Bull. Ju and Rogers (1996) excluded it from their narrower concept of Hypoxylon and placed it in Kretzschmaria (Rogers and Ju, 1998), relying on the following features that they do not consider referable to Hypoxylon:

-stromata strongly carbonaceous, usually more than 2 mm thick and loosely attached to the substrate, with white tissue between perithecia that progressively darkens and disappears, without KOH-extractable pigments;

-ascal apical apparatus higher than broad and ascospores with a germ slit on the less convex side and with indehiscent perispore;

- anamorph in nature referable to Geniculosporium Chesters and Greenalgh, palisadic, white to dark grey, covering the surface of young stromata.

Rogers and Ju (1998) separated two groups in Kretzschmaria, basing upon stromatal morphology: ustulinoid taxa with massive effused-pulvinate stromata that are loosely attached to the substrate ( K. deusta belongs to this group), and kretzschmarioid taxa that are stipitate, gregarious, with the fertile part less than 1 cm. diam, and stipes and/or fertile parts often fused together.This latter group is only represented by tropical or subtropical taxa.