S0fi9 



Arthur: Cultures of Uredineae in 191 i 55 



6. Uromyces Peckianus Farl., on Distichlis spicata (L.) 

 Greene, obtained in the field March 29, 191 1, at Pictou, Nova 

 Scotia, by Professor W. P. Fraser, was sown April 19 on Tissa 

 canadensis and Lcpidium viryinicum, with no infection. Another 

 collection with same data but obtained in the field April 13, 191 1, 

 was sown on Bursa Bursa- past oris, Lcpidium i-iryiuicitiu, Cory- 

 dalis nioutauum, Tissa canadensis, Cleome spinosa, and Atriplex 

 hastata, with no infection except on the last, which showed nu- 

 merous pycnia May 16, and an abundance of aecia May 22. 

 Still another collection with same data but obtained in the field 

 April 27, 191 1, was sown May 5 on Chenopodium album and on 

 the same six hosts as the last, with infection only on Atriplex, 

 showing pycnia May 17, and aecia May 29, both in abundance. 



A former attempt at cultures with this species proved futile, 9 

 but Professor Fraser 10 met with better success in cultures made 

 by himself during the same season of 1910. He was able to 

 abundantly infect both A triples hastata and Chenop odium album 

 from teliospores on Distichlis spicata. Material from his cul- 

 tures was most generously sent to the writer. Since then he has 

 sent material of his more extensive and important cultures of 

 191 1, which need not be specifically mentioned here, although 

 they strengthen the conclusions about to be stated. 



A careful morphological study of herbarium material, both as 

 collected in the field and as grow r n from cultures, shows no appre- 

 ciable difference in the gross or microscopical characters between 

 the several stages of Puccinia subnitens Diet, and Uromyces 

 Peckianus Farl., except in one particular the unilocular or bi- 

 locular condition of the teliospore. When the teliospore is two- 

 Gelled, as in the Puccinia, it is correspondingly longer than, but 

 essentially the same otherwise as the one-celled teliospore, found 

 in the Uromyces. The aecia in their peridial cells and aecio- 

 spores, and the uredinia in their appearance and in their uredinio- 

 spores, when taken by themselves are indistinguishable. The only 

 character with which to separate the so-called two species is the 

 presence or absence of a septum in the teliospore. 



Both the Puccinia and the Uromyces show marked racial tend- 

 encies in the selection of aecial hosts, seemingly correlated with 



9 See Mycol. 4 : 12. 1912. 



10 Mycol. 3: 72-74. 191 1. 



