COLEOSPORIUM 319 



is indigenous to North America. This family retains probably, 

 in the mode of germination of its teleutospore, a very primitive 

 character, but has nevertheless undergone a large amount of 

 recent evolution, and is no doubt worthy of subdivision. 



There is a North American species, belonging to the 

 Coleosporiacea 1 , which is deserving of great attention. It is 

 Oallowaya Pini Arthur (formerly Coleosporium Pini Galloway). 

 which has teleutospores only, and on leaves of Pinus inops, 

 i.e. on trees of the same order on which Coleosporium has its 

 secidia. Similarly, among the Melampsoracese, there is a like 

 case in Necium Farlowii Arthur, which has its teleutospores on 

 Abies canadensis, while various hetercecious Melampsoracea^, 

 with similar teleutospores on other (non-coniferous) plants, 

 have their aecidia on Conifers. Again in the Cronartiaceae, 

 Chrysomyxa Ledi and C. Rhododendri are hetercecious species 

 having their secidia on Picea excelsa ; but there is also 

 C. Abietis having its teleutospores on the same host (P. exceUu) 

 and no other spore form. Gymnosporangium bermudianum, 

 already mentioned (p. 304), furnishes a somewhat similar 

 instance. The evolutionary significance of these facts has not 

 yet been elucidated. 



COLEOSPORIUM Lev. 



iEcidia with a more or less cylindrical inflated peridium, 

 which opens by a cleft and becomes irregularly torn; secidiospores 

 with colourless membrane, without germ-pores, superficially 

 tuberculate, the tubercles somewhat deciduous. Uredospores 

 not enclosed in a peridium, abstricted in short chains, resembling 

 the secidiospores. Teleutospores in flat, waxy, indehiscent sori, 

 with a colourless gelatinous membrane, which is thin and wavy 

 at the sides but strongly thickened above, at first filled with 

 a rich orange-red oily mass ; at length each spore divides into 

 four superimposed cells, which in autumn can germinate in 

 situ as soon as mature, with a long sterigma. 



The species of Coleosporium are morphologically very much 

 alike, and are distinguished chiefly by their hosts. Moreover. 



