96 



COMPARATIVE MORPHOLOGY OF FUNGI 



1920) stimulates the neighboring Mucor hyphae to greater branching and 

 attracts them chemotropically. When a Mucor hypha reaches the 

 neighborhood of a growing hypha of Chaetocladium they cling together. 

 At the tip of the Chaetocladium hyphae, 3 to 8 nuclei collect and are 

 abjointed after about half an hour (Fig. 56, g). After another half-hour 

 the wall between the abjointed Chaetocladium cell and the Mucor hypha 

 is dissolved and the Chaetocladium cell, which is also called a cupping cell, 

 comes into direct communication with the Mucor hypha. Thereby, a 

 portion of the Mucor protoplasm with nuclei enters the Chaetocladium 

 cell (Fig. 56, h and i). The gall enlarges especially by the growth of 



Fig. 55. — Rhizopus nigricans. 1. Stolons, rhizoids and sporangiophores. 2, 3. Single 

 branched sporangiophores. 4. Sporangium. 5. Columella. 6. Sporangiospore showing 

 the epispore. 7. Swelling sporangiospore. (1, 2 X 8; 3 X 20; 4, 5 X 50; 6 X 1,200; 

 7 X 300; after Vuillemin and Wehmer.) 



that part of the Mucor hypha; thus it absorbs much oil and protein-like 

 substances from the Mucor and puts forth numerous short clavate or 

 cylindric outgrowths whose tips again fuse with the Mucor hyphae and 

 develop galls (Fig. 56, k). The Mucor nuclei, however, divide repeatedly 

 and are found especially at the tip of the outgrowths and at the top of the 

 galls. The hyphae of the Chaetocladium, which has been nourished 

 parasitically, grow around the gall which is continually branching further, 

 forming a cauliflower-like knob up to 0.5 mm. in diameter, from which, 

 after approximately 24 hours, the first sporophores develop, completely 

 emptying the gall. 



While in Chaetocladium the reserve is accumulated in the gall itself 

 and at a definite time is absorbed through the septum of the cupping cell, 



