A study was made of teliospores of Entorrhiza casparyana (Magn.) Lagerh. germinating in situ in degenerating root galls of Juncus articulatus and in galls stored in liquid media at 7 °C for 15 months. Teliospores germinating on agar were also examined. This is the first description of germination in this species. Teliospores germinated in situ and produced up to four aseptate promycelia each bearing up to four falcate sporidia, often distinctively looped or curved and in a terminal or subterminal position. On agar, teliospores germinated directly and formed septate branched hyphae but no sporidia. Karyokinesis occurred in the teliospores prior to germination. Division was presumed to be meiotic and to be followed by at least one mitosis. Cytokinesis followed, with up to four sectors being formed in a spore; this feature is described for the first time and appears to be unique to this genus. The mode of germination places Entorrhiza in the Tilletiaceae and also distinguishes it from Melanotaenium. The taxonomic position of the Ustilaginales is briefly discussed; the observations made so far on spore germination in E. casparyana support the retention of the Tilletiaceae in the Basidiomycetes.