Typhula Erythropus: II. Sclerotial Germination and Basidiocarp Production

SUMMARY

The influence of physical and nutritional factors on sclerotial germination and basidiocarp formation in Typhula erythropus was studied. Sclerotia produced in culture at 10–15 C germinated readily (carpogenically) when incubated on water agar at 4–10 C. Sclerotia grown to maturity at 4 C did not germinate unless activated while turgid by treatment at 15–20 C for 10–14 da. Viability was reduced by freezing or drying at 20 C, but was not affected by washing or by cold storage for up to 21 mo.

Basidiocarps arose in culture from sclerotia, inoculation plugs, and directly from the colonial surface. Development was arbitrarily divided into four morphological stages, and the expansion of the fructification approximated that process in agarics. The range of temperature for basidiocarp development from sclerotia was 4–10 C and 15 C for fructifications arising from the colony. Hymenial formation usually did not occur at 15 C or above or in darkness. Fruit bodies were positively phototropic. Mature basidiocarps were present 6–10 da after initiation and continued to sporulate for 10–15 da under favorable conditions.

The optimum pH for fruiting from the colony was near pH 6. Maximum basidiocarp production occurred on low-nutrient media and at a C/N ratio of 19:1. Thiamine was required for mycelial growth and basidocarp formation.

Several taxonomic characters were studied for their stability under varying conditions. Basidiospore dimensions were consistent, 5.5-7.5 × 2.4-3.6 μm. Basidiocarp coloration and proportions remained stable under most conditions, with stalk length and head length and width increasing with age. One to eight fructifications arose from single sclerotia.