THE FUNGI WHICH CAUSE PLANT DISEASE 369 



G. eUisii (Berk.) Farl. 



I. ^cium unknown. III. Telia on Cupressus thyoides. Prob- 

 ably of very small economic importance. 



G. transfonnans (Ellis) Kern. (=Roestelia transformans 



Ellis). 



I. iEcia on Pyrus arbutifolia, which is of no economic im- 

 portance. Confined to a small area from Massachusetts to New 

 Jersey. 



III. Telia unknown. 



G. nidus-avis Thax. ™. 217 



I. jEcia amphigenous, especially fructicolous, cylindric, 2-4 mm. 

 high by 0.4-6.7 mm. in diameter; peridium soon becoming irregu- 

 larly lacerate usually to base, slightly spreading; peridial cells, 

 seen in both face and side views, lanceolate in face view, 15-23 x 

 55-88 ft; linear in side view, 14-18 fi, thick, outer wall 1-.5 fi 

 thick, smooth, inner and side walls 5-7 fi thick, coarsely rugose 

 with narrow ridges, with shorter, often roundish papillae inter- 

 spersed; aeciospores globoid or broadly ellipsoid, 18-23 x 23-28 fi, 

 wall cinnamon-brown, rather thick, 2.5-4 n, very finely verrucose, 

 appearing almost smooth when wet. 



III. Telia caulicolous, often dwarfing the young shoots and 

 causing birds' nest distortions, or witches' brooms, usually causing 

 a reversion of the leaves to the juvenile form, sometimes appearing 

 on isolated areas on the larger branches and producing gradual 

 enlargements, solitary or rarely confluent, of variable size and 

 shape, roundish to oval on the young shoots, 1-2 mm. across, oval 

 to nearly elliptic on the woody branches, 1.5-3 mm. wide by 

 2-7 nmi. long, pulvinate when young, becoming hemispheric, dark 

 reddish-brown; 'teliospores 2-celled, ellipsoid, 16-23 x 39-55 n, 

 wall pale cinnamon-brown, rather thin, 1-1.5 ju, very slightly 

 thicker at apex; pores one in a cell, apical. Mycelium pereimial 

 in leaves, branches or trunks of Juniperus virginiana very com- 

 monly inducing a "bird's nest" distortion. 



I. iEcia on Amelanchier and quince. 



III. Telia on Juniperus virginiana. 



G. sabinse (Dicks) Wint. 



and I (=Rcestelia cancellata), on pear in Europe. 



III. Telia on several Junipers. 



