PUCCINIA. 353 



Iceland, Greenland, and Switzerland. Juel states that this is the only 

 heteroecious Puccinia whose uredo- and teleutospores inhabit a dicotyle- 

 ■donous plant. 



(2) Aecidia are absent ; pycnidia, uredospores, and teleutospores 

 developed on the same plant. {Brachypioccinia, Schroet.) : 



Puccinia suaveolens (Pers.) (Britain and U.S. America). 

 One form on Cirsium arvense, and a second on Centaurea Cyanus. 

 Pycnidia and uredospores appear first, then teleutospores develop 

 amongst the later-formed uredospores. 



The shoots and leaves of attacked plants are permeated with 

 mycelium and rendered conspicuous by their elongated shape, 

 lighter colour, and smaller, less lobed, softer leaves (Fig. 186). 

 Diseased plants bear no flowers. Wakker on investigating the 

 •diseased stems found : non-development of those sclerenchyma- 

 sheaths of the primary tissues situated towards the interior of 

 the stem, whereas those towards the outer side show secondary 

 thickening ; irregularities occur in the interfascicular cambium, 

 50 that the phloem becomes abnormally developed and propor- 

 tionately more extensive than the wood, it may also be divided 

 by a band of sclerenchyma. 



P. hieracii (Sohum.) (Britain and U.S. America). On numerous Com- 

 positae, e.g. CarLina, Cirsium, Gardims, Centaurea, Leontodon, Scorzonera, 

 Crepis, Hieracium, Ciehorium, etc. 



Plowright distinguishes two allied species on Compositae, viz. P. 

 ■centaureae, Mart, on Centaurea nigra, and P. taraxaci Plowr. 



P. bullata (Pers.) (Britain and U.S. America). On Umbelliferae, e.g. 

 Apium, Petroselinum, j^thusa, Selinum, Conium, Anethum, etc. On culti- 

 vated species (e.g. Parsley, Dill, Celery, etc.) it may prove troublesome.^ 



P. oreoselini (Strauss). On Peucedanum and Seseli. (U.S. America.) 



P. helvetica Schroet. On Asperula taurina. 



(3) Uredospores and teleutospores alone known. The related 

 pycnidia and aecidia have either not as yet been traced, or do 

 not exist. {Hemipuccinia, Schroet.) : 



Puccinia sorghi Schwein. {Puce, maydis Ber.). This rust of 

 Sorghum and Zea Mais occurs in America, Italy, Germany, etc. 

 The leaves become more or less beset with little pustules, in 

 which the sori of uredospores or teleutospores are contained 

 <Fig. 187-189). 



P. purpurea Cke. On Sorghum vulgare in India, and Zea in Africa. 



'Description and figures in N. J. Agric. Exper. Station Report, 1891. 



Z 



