DACRYOMYCETALES 



28S 



There is a single family, the Dacryomvcetaceae, which in- 

 cludes 7 genera and some 75 to 100 species. Considerable varia- 

 tion occurs among the various genera in the gross structure of 

 the fruiting body, which may be resupinate in Ceracea, pulvinate 

 in Dacryomyces, or stipitate in Guepinia. The basidiocarps of 

 the most complex genus, Calo- 

 cera, resemble a Clavaria in 

 miniature. Throusfhout the 

 group the fructifications are able 

 to survive considerable desicca- 

 tion, becoming shrunken and in- 

 conspicuous during dry weather. 

 In periods of rain, however, they 

 imbibe water, swell enormously, 

 and become brilliantly colored. 



In the common species Dac- 

 ryoviyces deliqiiescens young 

 fruiting bodies are orange col- 

 ored and produce only conidia. 

 The conidia are binucleate but 

 divide before germination to 

 form 2 uninucleate conidia, each 

 of which is capable of develop- 

 ing into a mycelium composed 

 of uninucleate cells [Dangeard 

 (1895)]. Conidial fructifica- 

 tions like those of D. deli- 

 qiiescens are unknoA\n in most 

 other members of the order. 



The surface of older fruiting bodies of D. deliqiiescens is cov- 

 ered by a hymenium consisting of narrow, closely compacted 

 basidia. Although it is known that the cells directly beneath the 

 hymenial layer are binucleate, the origin of the dicaryotic condi- 

 tion has never been satisfactorily explained. Clamp connections 

 have been observed in certain members of the order but appear 

 to be lacking in others. Gilbert (1921) states that anastomoses 

 between the cells of the developing fruiting body and division of 

 the single nucleus without accompanying cell division probably 

 explain the origin of binucleate cells. 



The developmental history of the basidium has been in dis- 



FiG. 112. Dacryomyces deliqiies- 

 cens. A. Section of hymenium. 

 The sterigmata project to the sur- 

 face of the jelly-like envelope. 

 B. Septation and growth of ba- 

 sidiospores. 



