460 COMPARATIVE MORPHOLOGY OF FUNGI 



consistent working out. The series of Amanitinae includes fleshy forms 

 whose spores possess no germ pore, as Lepiota (white spored, with ring, 

 without volva), Amanita (white spored, with ring and volva), Amanitop- 

 sis (like Amanita without ring) and Volvaria (pink spored without ring 

 with volva); the Pholiotinae includes similar types with ochraceaous 

 spores, with or without germ pore, among the fleshy forms Rozites (spores 

 warty), Pholiota (spores smooth), among the cartilaginous forms Tubaria 

 (lamellae decurrent); the Agaricinae with spores of various colors (not 

 ochraceous) with a germ pore, Psalliota (with ring, cap separable, spores 

 brown) Stropharia, (like Psalliota, pileus and stipe not separable), Hypho- 

 loma (with cortina, spores as Psalliota), Psathyrella, spores black, etc. 



Biologically, one species of Rozites is especially interesting. R. 

 gongylophora (Moller, 1893) in Brazil is cultivated by several genera of 

 ants, especially the leaf-cutting species (Atta sp.), in subterranean laby- 

 rinthine fungus gardens. The substance of these spongy masses consists 

 of an enormous number of little globules of up to }i mm. in diameter which 

 are formed from the kneaded-together remains of leaves which the ants 

 have carried into their nests as substrate for their fungi. In freshly 

 made spots they are dark green, in older almost black, and in still older 

 yellowish brown; they are permeated and loosely held together by white 

 hyphae. In the upper surfaces of the gardens, the hyphae join into 

 small fascicles measuring about 1 mm.; their ends become clavate and 

 filled with highly refractive protoplasm; these groups form the chief, 

 if not the only food for these ants. If the ants are removed and the 

 gardens abandoned (as also in artificial cultures) aspergilloid conidial 

 chains are cut off from the slightly clavate branches of the thick aerial 

 mycelium. In poor nourishment, peculiar pockets appear on the hyphae, 

 and the conidial fructification passes into a second stage with more oval 

 conidia which are cut off in long chains directly from the hyphae. 



It is noteworthy that in the cultivated strains of Psalliota campestris, 

 the basidia are mostly two-spored, in the wild strains usually four-spored. 

 Perhaps the two-spored condition is a sign of degeneration in the culti- 

 vated strains. 



Lactariaceae. — This natural family is characterized by decurrent, 

 comparatively thick, fragile lamellae and rough, echinulate, mostly 

 colorless spores. The tissue of the fructification, above all of the trama, 

 consists of a mixture of ordinary hyphae and of sphaerocysts generally 

 arranged in rosettes, thus appearing vesiculose to the naked eye. The 

 sphaerocysts are swollen, originally binucleate, hyphal cells, filled with a 

 clear liquid, whose nuclei fragment. Their ontogeny and function is 

 still unknown. 



In Lactarius rufus (Kuehner, 1926), the young primordium is differ- 

 entiated into an outer layer of vacuolate hyphae and an axis of slender 

 hyphae with prominent nuclei and reserves at the base of the fructification. 



