CARPOSPOREm. 2,^^ 



which produces the swelling of the leaf constituting the first stage which we considered, 

 a mycelium which bears spermogonia and aecidium-fruits. 



The genus Roestelia possesses no uredospores. Its aecidium-fruits which make their 

 appearance in July and August upon the leaves, petioles, and fruits of the Pomaceae 

 {Pyrus, Cydonia, Sorbus) resemble long-necked flasks and may become as much as eight 

 millimetres long ; they open either at their apices or laterally by means of slits. The 

 chains of spores present a peculiarity which occurs also in other instances, that between 

 any two spores there lies a sterile cell which subsequently decays. The teleutospore- 

 fruits belonging to Roestelia (formerly known as Gymno sporangium) appear upon species 

 of Juniperus in the spring as spherical, conical, clavate, tongue-shaped, or palmate gela- 

 tinous masses of a yellow or brown colour. They consist of closely-placed basidia 

 arising from the mycelium which extends beneath the epidermis of the leaves and in 

 the cortex of the branches, and bearing the teleutospores. The teleutospores resemble 

 those of jEcidium Berberidis, and like them produce promycelia on germination, the 

 sporidia of which reproduce Roestelia with aecidium-fruits upon the leaves of Pomaceae. 



Under the name of HypodermiesB De Bary unites the Uredineae with the Ustila- 

 gineae, which, however, do not seem to be very closely related to them, l^he 

 UstilaginesB ^ (Smuts) are parasitic in the tissues of Phanerogams, especially of Grasses, 

 in which their mycelium ramifies without at first effecting any injury. It is only when 

 the fructification, consisting of spherical dark-coloured conidia, is formed that the 

 vegetable organ in which it occurs becomes deformed : this usually swells up into 

 a vesicle, the whole of the internal tissue being absorbed and replaced by a black 

 powder, the conidia of the Fungus. Maize seeds are in this way converted by the 

 Ustilago Maidis into vesicles of the size of a nut, which, on bursting, liberate the 

 powdery conidia; Oats attacked by the smut are entirely filled with the conidia of 

 Tilletia caries. The germinating conidia produce a small promycelium which bears 

 sporidia : the hyphae developed from the sporidia penetrate into the sprouting grain 

 and the mycelium continues to grow until it produces conidia in the ears. 



C. The Basidiomycetes ^ 



Although this division includes the largest and most beautiful of the Fungi, yet 

 it is just here that our knowledge of their life-history is most imperfect. All that 



^s certainly known is that the basidiospores developed upon the large fructifications 

 consisting of masses of hyphse, germinate, forming mycelia, and that at a later 



Iperiod these mycelia bear fructifications. A development of sexual organs, by 

 leans of which the formation of the fruit could take place, has not as yet been 



[observed upon the mycehum ; still, a consideration of our knowledge with regard to 



Jthe Ascomycetes, more especially the Discomycetes, makes it at least probable that 

 the spore-producing fructification is to be regarded as a true fruit which owes its 



f^origin to the as yet undiscovered sexual organs existing upon the mycelium^. 



[However this may be, the whole process of development naturally divides itself in 



^ [Tulasne, Memoires sur les Ustilaginees ; Ann. Sci. Nat., ser. 3, VII, ser. 4, II. — De Bary, 

 [Unters, ueb. die Brandpilze, Berlin 1853. — Fischer von Waldheim, Aper9U systematique des Ustila- 

 ^ginees, Paris 1877. — De Bary, Protomyces microsporus und seine Verwandten, Bot. Zeitg. 1874.] 



^ See De Bary. Morphol. u. Physiol, der Pilze, Flechten, und Myxomyceten, Leipzig 1866. 



^ [From the researches of Brefeld (Basidiomycetes, 1877) it appears that these plants have no 

 fsexual reproduction. Their large fructifications are comparable to the asexual conidia-bearing 

 fructifications of the Ascomycetes, The so-called 'basidiospores' are, like the 'uredospores' and 

 teleutospores ' of the iFcidiomycetes, merely conidia.] 



