Morphology of Cronartium fusiforme Aeciospores: A Light and Scanning Electron Microscopic Study

The morphology and size of Cronartium fusiforme aeciospores collected from fusiform galls on slash and loblolly pines in East Baton Rouge Parish, Louisiana, were studied with light and scanning electron microscopy. The spore surface ornamentation was used as a taxonomic characteristic in distinguishing the C. fusiforme aeciospores from those of other Cronartium species. We concluded that the existence or nonexistence of smooth surface area, as well as the shape, size, arrangement, and ontogeny of surface projections in the verrucose area of the aeciospores, are sufficient for separation of most Cronartium species. Aeciospores of C. fusiforme and C. quercuum appeared to be identical.