THE UU.ST.S OF N()\A SCOTIA. — FKASER. 83T 



hasidiiim bearing- a siiigie sporo. A few ])otaiii~ts regard the 

 teliospore as an ascns in which the spore-wal] is niiited with 

 the ascus-wall, thns the rusts would })!'lr)iig in the ela«6 

 Asco7nycetes. 



The order Uredinales (Uredinae TuL) to which the *rusts 

 belong is divided by Dietel into four families : Melampsoraceae, 

 Coleosporiaceae, Oronartiaceae and Pucciniaceae. The separa- 

 tion is based on the character of the telia and the teliospores. 



Tn the Melampsoraceae the teliospores stand side by side 

 forming one-layered, flattened masses, which are separated with 

 difficulty; or they may be scattered in the tissues of the host, 

 tJien they are usually two- or fonr-celled ; the genus 

 Uredinopsis belongs to the latter group. The telios]x>res are 

 always sessile. 



In the Coleosporiaceae the teliospores are united into 

 one- or two-layered, light-coloured, waxy crusts. They gennin- 

 ate without a promycelium, the spore cell soon divides into four 

 basidia and each of these produces a large basidiospore about 

 20/Jt long. The teliospores are sessile except in a South 

 American genus Chrysopsora. 



The Cronartiaceae have sessile teliospores which are formed 

 in series and either separate from each other or remain united 

 in filiform masses, as in Cronartium, or are formed, in chains 

 and (•oiii])acted laterally fonnirig cushion-shaped masses as in 

 Chrysomyxa. 



The Pucciniaceae, which contain the well known rusts, 

 liave stalked teliospores either fasicled or free, usually easily 

 separable from the host plant, but sometimes, as in the genus 

 (lyninosponnigijUH, embedded in a gelatinous mass. 



Arthur recogTiizes three families: Coleosporiaceae, Uredin- 

 aceae (tbe latt(M- including Dietel's Melampsoraceae and 

 Gronar/iarcar). and Aeeidinccdc cori'espoiiding to Puccini- 

 (Irene. 



The following is a synopsis of the genera represented in 

 north eastern iSTorth America. It is largely based on Dietel's 

 J'Tediri'dcs in Die Xaffirlirheii f^flnnzcnfnmilim. 



