TREMELLALES 



523 



The systematic differentiation of these forms is very difficult because 

 marked morphological characters are lacking and because the form of 

 the fructifications, depending upon their environment, may alter beyond 

 recognition. The conidia are, therefore, often used to distinguish the 

 genera. 



The simpler genera, as Eichleriella, Exidia (Ulocolla), Ditangium 

 (C rater ocolla) and Tremella, are directly connected with Sebacina in the 

 structure of the fructifications. Eichleriella is 

 more or less coriaceous and bears the same rela- 

 tion to Sebacina which Stereum and Cyphella 

 bear to Corticium, E. spinulosa has a tuber- 

 culate hymenium resembling Radulum and 

 forms a transition to Protohydnum in the 

 Tremellodonteae. The other genera are gelat- 

 inous to cartilaginous, tuberiform to turbinate, 

 generally much lobed and branched, often 

 cerebriform (Figs. 341 and 342), bearing a 

 hymenium on the outer surface, but sterile 

 next the substrate. 



The higher genera, Gyrocephalus, Clavariop- 

 sis and Tremellodendron develop forms reminis- 

 cent of the higher families of the Polyporales. 

 Gyrocephalus forms stipitate, infundibuliform 

 fructifications, bearing the hymenium on the 

 inner side. In form they suggest Craterellus 

 cornucopioides and the Cantharellaceae. Clava- 

 riopsis forms cylindric or coralloid fructifications 

 similar to Clavaria, while Tremellodendron has 

 flattened branches, resembling Sparassis, Pterula 

 or Thelephora. 



In the basidia, the spindle is transverse at 

 the division of the diploid nucleus. At the end 

 of the first division, the first septum is laid 

 down from the basidial wall. The nuclei divide 

 again, their spindles are transverse and approximately parallel to the first 

 septum, hence perpendicular to the plane of division of the first nucleus. 

 After this division, a new septum is formed perpendicular to the first (Juel, 

 1898; Neuhoff, 1924; Kuehner, 1926). In the rare cases where the septa 

 are not always transverse, e.g., in Tremella compacta, they may be parallel, 

 as in the Auricularia type, or in T. lutescens, they may be irregular, (Fig. 

 343), or they may be absent. Sometimes the basidia, instead of 

 forming spores, may develop directly to mycelia. In Clavariopsis 

 prolifera, as in Eocronartium and Iola, new basidia are always formed 

 by lateral growth of the subterminal cells on the same hypha. 



Fig. 343/ — Tremella lute- 

 scens. Basidium with irregu- 

 lar septa, germinating to 

 mycelium. (X 720; after 

 Coker, 1920.) 



