‖ æcidium Bot.
(iːˈsɪdɪəm)
Pl. -a.
[mod.L., dim. of Gr. αἰκία injury.]
The cup-shaped fruit borne on the mycelium of certain parasitic fungi which especially attack the families Compositæ, Ranunculaceæ, Leguminosæ, and Labiatæ.
| 1867 J. Hogg Microsc. ii. i. 291 Producing chains of orange coloured fruit or in other words an æcidium. 1878 M'Nab Bot. 56 The mycelium gives rise to small fruit-like bodies, the æcidia. |