GROUPS OF SPORE-FORMS 39 



little flattened on one side, while in Ochropsora they are 

 spindle-shaped. This is one of the reasons for suspecting that 

 it is probably incorrect to classify these two latter genera in 

 the same family, on the basis of the " internal " basidium 

 merely. The genus Chrysopsora, which has the same kind of 

 basidium, belongs to the Pucciniacea?. 



Grouping according to Spore- forms. 



For certain purposes it is convenient to have names for the 

 groups into which the Uredinales may be divided according to 

 the number of spore-forms possessed by each, though it must 

 never be forgotten that such a grouping does not in any way 

 indicate affinity. The method usually employed is that put 

 forward by Schroter, which (with a little modification according 

 to present ideas) may be presented in the following scheme. 



Denoting spermogones by O, oecidia by I, uredospores by 

 II, and teleutospores (with the ensuing basidiospores) by III, 

 we call a fungus possessing 



fAuteu-form, if with all four on one 



plant. 

 Hetereu-form, if O, I on one species, 

 and II, III on another, 

 an -opsis-form. 

 a Brachy-form. 

 a Hemi-form (in many cases perhaps the half of a 



Hetereu-form). 

 a Micro-form (spermogones sometimes absent). 



Thus Melampsora Rostrupii is a Eumelampsora, Gymno- 

 sporangium Sabinae is a Gymnosporangiopsis, Uromyces Anthyl- 

 lidis is a Hemiuromyces, and Puccinia Ca7npanulae is a Micro- 

 puccinia. A Leptoform is one, of whatever kind, in which the 

 teleutospores germinate as soon as mature, without any resting 

 period ; thus the spores of P. Malvacearum belong chiefly to 

 the lepto-form, those of Endophyllum Sempervivi entirely so. 



Maire (Progress. Rei Botan. 1911, iv, 115) has proposed a 

 much more complex arrangement on the same lines, which is 

 quite needless and, it is to be hoped, will be quietly ignored. 



O I II III a Eu-form 



