FUNGI. 461 



The host-plants affected by the same species are usually of two very 

 different kinds. The teleutospores and Uredospores afiect chiefly the 

 Graminece., and prove very destructive to that useful order of plants. The 

 ^Ecidium spores are not so much confined to one order of plants, but affect 

 usually the Composites, Ranunculacea, Leguminosce, and Labiatce, to which 

 they are by no means so destructive as the teleutospores and uredosporea 

 are to the Graminece. 



Until recently the different generations of these Fungi were taken to 

 represent different genera, and even now they are, we need not say erro- 

 neously, so described by many mycologists on the plea of convenience. 

 The ^Ecidiumspores represent the genus u jSZcicKttm" the Uredospores 

 " Uredo" and the teleutospures " Puccinia" and " T7romyces." Each 

 generation of each species has its peculiar host-plant, and of a not incon- 

 siderable number there is only known one or two generations the JEd- 

 dium only in some cases, and the Uredo and Puccinia only in others. 



To M. Tulasne and Professor de Bary belong chiefly the honour of 

 having worked out this remarkable life-history. 



Suborder 2. USTILAGUSTE^. Fungi parasitic on living plants, 

 and consisting of interwoven hyphae, which bear asexual spores 

 irregularly. Spores sooty-coloured, either solitary, in series, or in 

 masses, at first enclosed, but at length bursting out and escaping 

 easily, from the slender nature of the threads which bear them. 

 The whole life-cycle, so far as yet known, consists in the forma- 

 tion by the germinating spores of sporidia, which, on suitable host- 

 plants, germinate and form a mycelium on which the spores are 

 again directly formed. Illustrative Genera : Ustilago, FT. ; Til- 

 letia, Tul. 



Structure and Life-history. The habit of life of this order is similar to 

 that of the preceding one. In it the life-history, so far as it goes, is also 

 of the same nature. When the spores, which correspond to the teleuto- 

 spores of Uredinea, germinate, a promycelium is formed as in that Order, 

 bearing sporidia, in some cases sessile and in others slightly stalked. It 

 appears also that successive sporidia may be formed at the same place. 

 These sporidia germinate in the usual manner and form a new mycelium 

 in the tissues of a suitable host-plant, which mycelium directly produces 

 again the spores from which we started. The Ustilaginece are very in- 

 jurious, especially to the Graminece. Kuhn and Hoffmann observed that 

 the sporidia attack the axis of the germinating plants, in which they de- 

 velop a mycelium, which is carried up with the growing plant, and 

 ultimately produces spores in the fruits and causes their destruction. The 

 power of producing successive sporidia tends largely to cause the plentiful 

 distribution of the Order. 



BASIDIOMYCETES. 



Diagnosis. Fungi growing on dead organic matter and stumps 

 of trees, and consisting of hyphse interwoven, so as to form a fleshy, 

 gelatinous or woody thallus (vulgarly considered the plant), but 



