384 



of the rusts, even by the foremost students of the order. It affects sys- 

 tematic work adversely, keeps the terminology in an antiquated and ambig- 

 uous form, and makes it difficult to institute legitimate comparisons be- 

 tween different genera, species, or spore structures. 



One of the wrong conceptions, wrong when viewed in the light of 

 present knowledge, is to make the genus Puccinia include all species that 

 possess a two-celled, pedicelled and free teliospore (excepting those with 

 teliospore imbedded in gelatinous matrix, separated under Gymnospor- 

 angium), irrespective of the other morphological characters, or of the 

 complexity of the life cycle, and furthermore, as part of the same concep- 

 tion, to make the genus Uromyces include all species that possess the same 

 kind of teliospore, only one-celled instead of two-celled. The writer be- 

 lieves that the length and nature of the life cycle, which is a more unvary- 

 ing character in the rusts than the one or two-celled teliospore (recall 

 the Uromyces-Puccinia species on Allium, Sida. and some other hosts), 

 should be accepted as a character for genera, as it is now quite generally 

 accepted for species. Recognizing this as a valid generic character, and 

 taken in connection with other characters, the genus Puccinia can be sep- 

 arated into four genera (i. e., Dicceoma, Allodus, Bullaria. Dasyspora), 

 and the genus Uromyces also into four (i. e.. Nigredd, Uromycopsis, Ele- 

 bahnia. Telospora). If other characters, as well as the life cycle, mostly 

 now generally ignored, are taken into account, Puccinia Pruni-spinosce and 

 its allies should form a genus (Transschelia) near to RaveneUa, on ac- 

 count of the adherent pedicels of the teliospores and peculiar structure 

 of the urediniospores ; Uromyces rosicola, on account of its evident spore 

 structure, will go into a genus (Ameris) near to Pliragmidium. but with 

 a more limited life cycle; Uromyces Tereointhi. and its allies, on account 

 of the remarkably distinctive characters of both urediniospores and telio- 

 spores. will form a genus somewhere between RaveneUa and Tranzschelia. 

 while the similar Uromyces effusus, with a still more restricted life cycle, 

 will go into another genus (Discospora). And in like maimer quite a num- 

 ber of other species now commonly included under Puccinia and Uromyces 

 could properly be separated and distributed to other genera, with much 

 improvement in the nomenclature and great clarification of the systematic 

 affinities. Other genera beside Puccinia and Uromyces could also be shown 

 to be overburdened with species whose life cycle, or morphological struc- 

 ture, or both, entitle them to a different place in the systematic arrauge- 



