Nov., 192 1 ] MAINS RUSTS ON NYSSA AND URTICASTRUM 447 
Nyssa rust principally in the catenulate method of spore formation, the 
teliospores developing in chains of two or three (figs. 4, 5). The terminal 
Fig. 4. Section through young telium of Cerotelium Dicentrae showing catenulate character 
of the tehospores. 
Spore of these chains often germinates before the lower spores are fully 
developed, and it may be that more spores are produced from the sporog- 
enous cell than show at any one time. The catenulate character of the 
teliospores indicates that this species is related to a group consisting of 
such genera as Phakopsora (Physopella, Bubakia, Schroeteriaster), Uredo- 
peltis, Melampsoropsis, Chrysomyxa, Baeodromus, Alveolaria, and Cero- 
telium.* In Alveolaria the arrangement of the teliospores in definite layers 
which separate from each other, and in Baeodromus the colored thick- 
walled teliospores with delayed germination, taken with the short life 
Fig. 5. Section through mature telium of Cerotelium Dicentrae showing germination of the 
teliospores. 
