(449) 



recent studies, supplemented by cultures, have shown the incor- 

 rectness of this interpretation. This species nearly always produces 

 a fasciation of the branch system, forming witches' brooms, and 

 usually causes the leaves of the affected parts to take on the sub- 

 ulate juvenile form. The real G. Nelsoni of Arthur does not pro- 

 duce such distortions but appears on gall-like enlargements and 

 appears without doubt to be identical with the writer's G. durum. 

 There are also other differences in the character of the telia and 

 teliospores. Both species have aecia on Amelanchier, which re- 

 semble each other very much in gross appearance, and this fact 

 has been partially responsible for the confusion. 



15. Gymnosporangium Kernianum Bethel, Mycologia 3: 157. 

 1911 



Aecia unknown. (Cultures are now in progress but as this paper 

 goes to press no aecia have yet developed.) 



Telia caulicolous, arising between the scale-like leaves on the 

 green twigs, causing a fasciation of the young shoots and forming 

 globose witches' brooms 5-60 cm. in diameter, not causing a 

 reversion to the juvenile form, scattered, usually solitary, hemi- 

 spheric, 0.5-0.8 mm. across, rather compact, dark reddish-brown; 

 teliospores chiefly 2-celled, narrowly ellipsoid, 21-26X55-74/*, 

 narrowed or sometimes rounded at both ends, slightly or not con- 

 stricted at the septum, wall thin, about iju, yellowish; pedicel 

 cylindric; pores usually 2 in each cell, near the septum. 



For the aecia : Amelanchier spp. 



For the telia: Juniperus utahensis (Engelm.) Lemm. (Sabina 

 utahensis Rydb.). 



Type locality: Paonia, Colorado, on Juniperus utahensis. 



Distribution: Known only from western Colorado. 



Illustrations: Mycologia 3: 158,/. ia, pi. 48, f. 2. 



In the small size of the telia and in their manner of arising be- 

 tween the scale-like leaves, this species has a superficial resemblance 

 to G. inconspicuum and G. multiporum but differs from them in 

 causing witches' broom distortions of the branch-system as well 

 as in several pronounced microscopic characters. It differs from 

 G. inconspicuum in having a cylindric instead of carotiform pedi- 

 cel, from both G. inconspicuum and G. multiporum in the number 

 and arrangement of the germ-pores, and from G. multiporum also 

 in the size and shape of the teliospores. In its tendency to pro- 



