SECT. in. UREDINES: 277 



taining two conidia or spore cells. These fungi were 

 crowded together in multitudes in a small space so as 

 to form a solid rounded mass, with their broad tops 

 immediately under the skin of the upper-side of the leaf, 

 but sometimes they were arranged in concentric circles. 

 The TJredines, on the contrary, had colourless branch- 

 ing stems, like threads, bearing on their tops pointed 

 spore sacs. In some species these Uredines are scattered 

 through the mass of Puccinia, in others disposed in a 

 circle round it, or in the centre of the concentric ring 

 where the Puccinia takes that form. It was long be- 

 lieved that these two forms of fungi living together in 

 the same cavity were totally different plants, but as in 

 various instances M. Tulasne perceived that the Uredo 

 had sprung up, shed its spores, and vanished before its 

 companion had ripened its fruit, he concluded that the 

 two different forms are merely two states of the same 

 plant, that the larger spores of the Uredo thus early 

 matured, immediately germinate and produce the Puc- 

 cinia, whose fine dust-like spores are merely the secon- 

 dary fruit of the Uredo. These minute spores issue 

 through a pore in the conidia or dust cell and a puncture 

 in the upper skin of the leaf into the air, whence they 

 are wafted in myriads by the winds ; and, if not too late 

 in the season, they enter into the pores of the leaves and 

 tender parts of the same or other plants that may suit 

 them, and within these they form a mycelium, and 

 produce a young Uredo. Even if the autumnal leaves 

 fall in a moist place before the spores have germi- 

 nated, the entophyte will grow on the approach of 

 spring, and ultimately send its dust spores to enter into 

 young leaves, and grow with their growth. 



Although there cannot be a doubt of the existence of 

 the Uredines as a numerous natural family, M. Tulasne 

 considers the species of certain genera to be only se- 

 condary forms of certain genera of Puccinise. Many 



