546 COMPARATIVE MORPHOLOGY OF FUNGI 



as zeugites. In the case of /. javensis of the damp mountain forests 

 of West Java, after an hour in free air with a relative humidity of 70 

 per cent and a temperature of 26° C. in the shade, the fructifications 

 collapse. Returned to a crystalizing dish saturated with moisture, 

 they resume somewhat the former appearance in the course of a week. 

 If the relative humidity in the forest does not drop below 90 per cent, 

 that prevalent in the rainy season on the moss carpet between the under- 

 growth, the conditions of life are fulfilled. If the stores of nutrients 

 which on the advent of high humidity may be used for basidial formation 

 are not collected in the probasidium during a relative drought, the whole 

 life process is at a standstill and the first basidia do not appear until 

 4 to 7 days after the resumption of growth. Hence in this species, the 

 probasidia are not in a position to carry the fungus over unfavorable 

 conditions as we shall find in subsequent groups. The hyphae within 

 the sporogonium alone remain intact. 



A second factor is air temperature. The lower limit for basidial 

 formation lies at 15° C, the optimum between 18° and 26° with a maxi- 

 mum at 30°. Measurements taken under natural conditions have shown 

 that only in the late morning are these limits exceeded and that after 

 sunset the temperature again falls below the minimum. New basidia 

 may only be formed during a short time. Therefore it appears that 

 the probasidia are storage organs in which reserves are accumulated 

 and meiosis occurs, so that when temperature relations are favorable, 

 basidia may be formed more rapidly. If the humidity is sufficient, 

 and the temperature below 15°, only preparation occurs, while as soon 

 as the temperature rises above this limit, the basidium is protruded 

 above the gel. The function of protection is probably assumed by the gel, 

 since fructifications containing a gel are usually very resistant to cold. 

 In Cystobasidium, which lacks a gel, the zeugites develop as organs 

 of protection. C. Lasioboli (Lagerheim, 1898) forms arachnoid covering 

 on the fructifications of Lasiobolus. Occasionally the hyphae have 

 clamp connections. On short branches they form probasidia whose 

 walls are considerably thicker than those of the basidia which arise from 

 it or than those of the hyphae (Fig. 364, 9 and 10, Sc). The basidio- 

 spores germinate in nutrient solutions by "sprout" conidia. The pro- 

 basidia of this species unite in themselves the ecological functions of 

 resting organs and of protective organs. Since they are encysted they 

 will be called sclerobasidia and are homologous with the teliospores 

 of the Uredinales. 



In Saccoblastia, whose only carefully studied species is S. ovispora 

 (Moller, 1895; Coker, 1920) found in Brazil and North Carolina on the 

 bark of trees, the mycelium forms a delicate, almost transparent covering. 

 On this there project somewhat thinner hyphae whose terminal cells, 

 as in Iola, occasionally swell slightly (Fig. 364, 11, p), and form lateral, 



