DEVELOPMENTAL MORPHOLOGY AND CYTOLOGY

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Genus Kretzschmaria
Key to Taxa of Kretzschmaria
Accepted Taxa
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Jack
Yu-Ming Ju
Michael J. Adams

 The Tulasne brothers recorded and illustrated the general development of K. deusta (as Ustulina vulgaris) from stromatal initiation through conidial production, ascospore maturation, and senescence (Tulasne and Tulasne, 1863). Miller (1928) likewise did a preliminary study of teleomorph development. Wilkins (1935) did a comprehensive study of the decay caused by K. deusta (as U. vulgaris) on Tilia vulgaris Hayne, recording the microscopic effects of the fungus on wood. He concluded that the fungus causes a disease of the standing tree, a white rot of the wood. He did a detailed study of the morphology of ascospore germination and the influence of environmental conditions and proved that germ tubes can penetrate wood (Wilkins, 1938). He later did a detailed study of conidial germination and showed them to be infective propagules that are at least as effective as ascospores (Wilkins, 1939a).

Jong and Rogers (1972) described the anamorph of K. deusta (as Hypoxylon deustum). They concluded that the sporodochium-like arrangement of conidiophores agrees more with that of Xylaria than of Hypoxylon and, further, that Ustulina deusta is the binomial that most closely indicates the taxonomic position of the fungus.

Rogers (1968) reported the chromosome number of K. deusta (as Hypoxylon deustum) to be n=4. Ascospores are at first uninucleate, become binucleate via a mitosis, then mature in a uninucleate condition following the disintegration of one of the daughter nuclei. Later studies (unpublished) utilizing fluorescence microscopy showed that the disintegrating nucleus is, in fact, in a cellular appendage that is obliterated during ascospore maturation. This is a common feature among Xylaria species (Rogers, 1979).