COMPLEX SMUTS. 91 



allied to the preceding, are included botanically 

 under tiie genus called Pohjcystisj in allusion to tlie 

 many cells of wliicli the spores are composed.* In 

 one of the recent works on British Fungi, approxi- 

 mating to a Flora — viz., ^' Berkeley's Outlines " — 

 only three species are recorded, whilst the most 

 common, at least around London, is omitted in 

 error ; for it could scarcely have been unknown as 

 indigenous to this country. This last is the crow- 

 foot smut {Polycystis pompliolyrjocleSy Lev.), found 

 on the leaves and petioles of the common creeping 

 buttercup [Uanunciilus rejpens), distorting them 

 very much, and also occurring on the wood-anemone 

 and some other Ranunculaceous plants. The leaves 

 and their footstalks, when attacked, become swollen, 

 as if blistered at first, and ultimately burst in an 

 in*egular manner, exposing a mass of blackish 

 soot-like dust (plate IX. fig. 183), which on exa- 

 mination will be found to consist of the many-celled 

 spores alluded to (plate IX. fig. 184). Each of 

 these spore masses consists of a few coloured cells 

 or true spores in the centre, surrounded by other 

 colourless and abortive cells, or pseudo- spores. 

 The whole mass takes a somewhat globose form,. 

 Sometimes one spore-mass includes not more than 

 one or two central, or true, spores, the rest being 

 colourless and barren. As may be anticipated, 



* Eabenhorsfc has proposed Uroajstis as the name of this 

 genus, on the ground that Polycystis was priorly applied to a 

 genus of Algse. Hence Urocystis is now universally adopted. 



