The spores of Rusts, Erysipheae an d other Fungi may be conveyed from plant to plant by snails; those of tree-killing polyporei, &c., by mice, rabbits, rats, &c., which rub their fur against the hymenophores.
The wheat-rtist costs Australia 2,000,000 to L3,000,000 annually, and in 1891 alone the loss which Prussia suffered from grain-rusts was estimated at 20,000,000 sterling.
Gymnosporangium sabinae, one of the rusts (Uredineae) passes one stage of its life-history on living pear leaves, forming large raised spots or patches which are at first yellow but soon become red and are visible on both faces; on the lower face of each patch is a group of cluster-cups or aecidia containing spores which escape when ripe.
" Iron " (Liao), he said, " rusts, but gold always keeps its purity and colour, therefore my dynasty shall be called Kin."
Iron, when exposed to moisture and air, "rusts"; but this process never takes place in the absence of air, and it is questionable whether it ever sets in in the absence of carbonic acid.