Abstract: Nutrition, pH, temperature, moisture, light, and aeration as factors influencing mycelial growth, primordia formation, and development of sporophores of 25 species of basidiomycetous macrofungi were studied, of which 18 species produced normal or nearly normal fruit-bodies in the laboratory. It was found that various agricultural by-products and farm wastes, such as sawdust, wood shavings, fallen leaves, soybean hay, bean pods, corn culms, paddy straw, rice glumes, wild grasses, etc. enriched with 20%–25% by weight of rice or wheatbran, made suitable substrata for most of the lignicolous species investigated with the exception of Tremella fuciformis and Lentinus edodes, and that well fermented dungs of domestic animals, such as horse, cow, pig, sheep, rabbit, and poultry, appeared to be satisfactory substitutes for bran as accelerators for fructification. Yields of carpophores were more or less directly proportional to the percentages of accelerators added to the substratum. The vegetative growth of the majority of species studied took place over a wide pH range of 3.0–8.0, with the optimum at 5–6, while the optimal pH for Ganoderma lucidum, Lentinus edodes, and Hericium erinaceus being about 4.0 and the maximum pH limit for H. erinaceus only 5.4. In Auricularia hispida, the pH range for fructification and that for mycelial growth were almost the same, but in Collybia velutipes and Agaricus bitorquis the pH range for sporogenesis was much more restricted, the optimal being 5–6 and 7–8 respectively. Most of the species investigated produced mycelium within a temperature range of 6–36℃, the optimum being about 24–27℃. However, the optimal temperatures for Auricularia auricula, Poria cocos and Volvariella volvacea var. heimii were found to be 30℃ or more. The temperatures required for sporophore and for primordia formation varied from species to species. While the fruit-bodies of Lentinus edodes and Pleurotus sapidus appeared only after "chilling", temperature fluctuations did not exert any stimu- lating effect on primordia differentiation in some other species. Using the temperature requirement for the initiation of primordia as the criterion, the species studied were grouped into the following categories: (1) high-temperature species, such as Ganoderma lucidum, Pleurotus rhodophyllus, Collybia radicata, Volvariella bombycina, and Volvariella volvacea var. heimii, with their optimum and maximum tem- peratures for primordia initiation exceeding 24℃ and 30℃ respectively; (2) intermediate species, such as Auricularia auricula, Tremella fuciformis, Pleurotus citrinopileatus, Pholiota adiposa, Agaricus bitorquis, and Agaricus rubellus, with their maxima not exceeding 28 ℃ and with the optimum lying within 20–24 ℃; and (3) low-temperature species, such as Auricularia hispida, Hericium erinaceus, H. caput-medusae, Pleurotus sapidus, Lentinus edodes, Collybia velutipes, and Agaricus bisporus, with their maxima not exceeding 24 ℃ and with the optimum under 20 ℃. Thus, under natural climatic conditions of a given region, without artificial heating or cooling, it was deemed practicable to arrange, according to the temperature response of the various species, a series of mushroom crops to be grown in rotation the year round. Moisture was found to have considerable influence on vegetative growth as well as reproduction. Most of the lignicolous species grew well on the sawdust medium, which contained 100%–340% by weight of water. Moisture content between 260%–340% was more favourable for fruiting, and several flushes were secured. At 100% moisture, fruiting was considerably delayed and only one flush of poorly developed carpophores was obtained. Aeration also played an important role in basidiocarp development. Stagnant humid air or CO2-laden atmosphere markedly inhibited pileus development, diminishing the size of pilei and causing morphological abnormalities. Adequate supply of fresh air with 80%–90% relative humidity tended to maintain a normal rate of transpiration, thereby guaranteeing a flourishing crop. In some species, such as Ganoderma lucidum, Tremella fuciformis, Pleurotus sapidus, Pleurotus citrinopileatus, Volvariella bombycina, Hericium erinaceus, Auricularia hispida, Armillaria mucida, and Lentinus edodes, light was found to be absolutely necessary. In these species, primordia formation would not commence until exposed to light. Certain other species, such as Auricularia auricula, Pleurotus rhodophyllus, Collybia velutipes, Pholiota adiposa, and Agaricus bitorquis, were able to fructify in total darkness, though their primordia formation was promoted by light. For the normal development and pig- mentation of fruit-bodies, light appeared to be essential. Morphological abnormalities, such as long slender stipes and thin rudimentary pilei occurred in total darkness. Results of experiments indicated that in most of the species studied, light reduced mycelial growth. The inhibitory effect was mainly due to the blue region (380–540 mμ) of the visible spectrum rather than the red region (570–920 mμ). On the contrary, light at the blue end was shown to be most effective and even essential for fructification; the red end being similar to darkness, evoked almost no response. Having analyzed the results obtained, it seems reasonable to assume that the ontogeny of higher Basidiomycetes consists most probably of four developmental stages, viz., (1) the stage of vegetative growth, (2) the stage of primordia initiation, (3) the stage of sporophore development, and (4) the stage of basidiospore formation, each of which has its own physiological characteristics and metabolic speciality.Hence the requirements of the various stages differ considerably.