39° NOTES AND COMMENTS [december 



other features. Triphragium clavcllosum, for example, is confined to 

 Aralia nudicaulis, and differs from T. Crcdelae, which lives on Credela 

 chinensis, merely by the size of the spores, a difference which does not 

 exceed the dimensions of a single micron. 



Such forms must obviously be looked upon as having sprung from 

 a common ancestor, which in this case must have lived on both hosts 

 indifferently, especially as the two species agree in the possession of 

 characters which distinguish them sharply from all other Triphragia. 



Another example is supplied by Leptopuccinias like P. Arcchavaletae 

 living on Sapindaceae, P. heterospora on Malvaceae, P. Elytrariae on 

 Acanthaceae, and P. Lantoneae on Verbenaceae, all of which closely 

 resemble each other in the form of their spores and spore-beds ; while 

 all possess in common such distinctive characters as the preponderance 

 of unicellular teleutospores, isolated individuals of which may reach a 

 much greater size than their fellows, and the occasional occurrence of 

 isolated bicellular spores which also vary in size, and the septum of 

 which is often oblique, while the only morphological differences are to 

 be found in slight diversities in the size of the spores and in the 

 thickness of their walls. 



Further evidence of the same kind is furnished by the only three 

 Puccinosiras known, and may probably be found in a number of other 

 heteroecious forms. 



A striking morphological resemblance is also observable between 

 certain Leptopuccinias and the teleutospores of heteroecious species 

 parasitic on widely different plants, but possessing aeciclia which live 

 on the same hosts as the Leptopuccinias in question, e.g. Puccinia 

 aecidii leucanthemi, which forms aecidia on Chrysanthemum 

 leucanthemum, gives rise on Carex montana to teleutospores which 

 closely resemble those borne by the Lepto-form Puccinia leucanthemi 

 on the former host. 



Professor Dietel cites a large number of such correspondences, and 

 believes that they point to the origin of the heteroecious and Lepto- 

 forms in a common ancestor inhabiting such widely different hosts as 

 Carices and Composites, while, on the other hand, Professor Magnus is 

 of opinion that the resemblance is purely accidental, and ascribable to 

 the great similarity existing among Leptopuccinias as a whole, owing 

 to adaptation to their peculiar mode of life. 



The coronate Puccinias, including, along with those heteroecious 

 species which form their aecidia on Rhamnus, the two Leptopuccinias 

 also living on the same host, and P. Festucae, which forms its aecidia 

 on Lonicera, are distinguished from all other Uredines by the possession 

 on the teleutospores of a crown of processes which appear to be devoid 

 of adaptational significance, and must be considered as pointing to a 

 common ancestry for these forms, especially as the only other Uredine 

 inhabiting Lonicera, is Puccinia longirostris, in which the crown is 

 replaced by a single long process on the apex of the teleutospore, but 



