3o6 DISEASES OF CULTIVATED PLANTS 



by Pucdnia coronata (Corda), characterised by the apex of 

 the teleutospore bearing a varying number of blunt pro- 

 jections. The aecidia form irregularly shaped yellow blotches 

 on the under surface of living leaves, also sometimes on the 

 flowers and fruit of various species of buckthorn (Rhamnus). 



The uredo and teleutospore stages usually occur on the 

 upper surface of the leaves, less frequently on the leaf-sheaths, 

 culm, and chaff of wheat, barley, rye, and many kinds of 

 wild grasses. The minute black teleutospore sori often form 

 irregular rings. 



Aecidia on irregular yellow patches on the under surface 

 of the leaves, especially along the nerve, also on the flower- 

 buds and fruit. Spores spinulose, 18-25 X 14-19 /*. 



Uredo sori orange-red, narrow and elongated, mostly on 

 the upper surface of the leaf, rarely on the leaf-sheath, culm, 

 or glumes; spores globose or broadly elliptical, spinulose, 

 yellow, 20-32 /u, or 21-32 X 20-24 /* 



Teleutospore sori blackish, small, numerous, often forming 

 rings on the leaf, surrounded by brown paraphyses; spores 

 shortly stalked, mostly clavate, apex truncate, with a variable 

 number of processes of variable length, 25-57 long, basal 

 cell 8-19 n wide, terminal cell 10-19 A* wide. 



Pucdnia dispersa (Eriks. and Henn.) forms its aecidium 

 stage on alkanet (Anchusa arvensis and A. offidnalis) as 

 irregularly elongated patches on living leaves, stems, flowers, 

 and fruit. Uredo and teleuto stages on leaves of wheat, rye, 

 and wild grasses belonging to the genera Bromus, Trisetum, 

 and Triticum. 



Aecidium stage forming large orange patches on stem, 

 leaves, and calyx; spores spinulose, 20-30 /* diam., or 



20-3O X 19-22 fJL. 



Uredo sori small, i mm. long, and nearly as broad, crowded 

 in groups on the leaves, ochraceous brown ; spores globose 

 or broadly elliptical, spinulose, yellow, 19-29 /* diam. 



Teleutospore sori blackish, irregularly scattered on the 

 under side, rarely on the upper side of the leaf, surrounded 

 by curved brown paraphyses ; spores shortly stalked, mostly 

 elongated and club-shaped, unsymmetrical, 40-50 fj. long, 

 terminal cell 14-19 p broad ; promycelium colourless. 



Pucdnia glumarum^ Eriks. and Henn. ( = Pucdnia rubi- 

 govera, D. C), is a widely distributed and destructive species, 

 infecting wheat, barley, oats, and many wild grasses. 

 Aecidium stage unknown. 



