Again, the curious distortions on the stems of nettles attacked by the Aecidium form of the heteroecious Puccina (]aricis (see FUNGf for Heteroecism), or on maize stems and leaves attacked by Ustilago Maydis, or on the inflorescence of crucifers infested with Cystopus, &c., are not individually very destructive; it is the cumulative effects of numerous attacks or of extensive epidemics which eventually tell.
Fungus-galls on leaves and stems are exemplified by the pocket-plums caused by the Exoasceae, the black blistering swellings of Ustilago Maydis, the yellow swellings on nettles due to Aecidium, &c.
Thus the Zulu says to the ancestral ghost, "Help me or you will feed on nettles"; whilst the still more primitive Australian exclaims to the "dead hand" that he carries about with him as a kind of divining-rod, "Guide me aright, or I throw you to the dogs."
Ashes particularly rich in potash are those of burning nettles, wormwood (Artemisia absinthium), tansy (Tanacetum vulgare), fumitory (Fumaria officinalis), and tobacco.
Formica), in stinging nettles, in some mineral waters, in animal secretions and in muscle.