Pilobolus umbonatus Buller and P. crystallinus Tode grew normally in a nitrogen atmosphere but their sporagnia were non-pigmented. When palced in anaerobic jars along with obligately anaerobic and obligately aerobic bacteria, the fungi grew in the range of oxygen concentrations too low for growth of the aerobic bacterium, but high enough to prevent growth of the anaerobe. The fungi did not grow when the oxygen was depleted to the point that allowed growth of the anaerobic bacterium. Catalase was not produced by the hyphae and trophocysts which normally grow beneath the surface of the medium, but was present in the aerial portions of these fungi. It is concluded that vegetative growth of P. umbonatus and P. crystallinus can occur under microaerophilic conditions but not under truly anaerobic conditions.
Pilobolus umbonatus and P. crystallinus grew and sporulated on nutrient broth, nutrient agar, tryptic soy broth, tryptic soy agar, and glucose-asparagine agar when hemoglobin or nicotinic acid were added to these media. The growth-enhancing effect of hemoglobin was most pronounced at a low pH. Page\u27s observations that species of Pilobolus have an alkaline optimum pH and require thiamine for sporulation were confirmed. A spinach extract agar medium without further supplementation also provided for growth of these fungi. The hemoglobin media are transparent, easy to prepare, and convenient for routine culture maintenance, morphological studies, and classroom work with Pilobolus, and semi-synthetic hemoglobin media similar to the glucose-asparagine medium may be useful in some physiological studies