336 DISEASES OF CULTIVATED PLANTS 



which become discoloured and soon die. Spores variable in 

 form, yellowish ; echinulate, 24-25 x 16-23 H- 



Uredo satyrii (Massee) attacks living leaves of Satvrium 

 coriifolium (Swz.) in South Africa. Cultivated specimens of 

 this orchid are destroyed by the fungus. Differs from Uredo 

 orchidis (Wint.) in the spore-clusters not being arranged in 

 regular concentric rings, and in the colourless spores. 



Spots indistinct; spore- clusters very numerous, mostly 

 epiphyllous ; spores globose or ovate, subhyaline, minutely 

 warted, 24-27 /x, or 25-30 x 16-1S /*. 



Massee, Kew Bulletin, 1809, p. 217. 



Uredo tropaeoli (Desm.) forms small, scattered pustules on 

 the under surface of the leaf. Spores powdery, elliptical or 

 rarely globose, orange, 16X10/X. On cultivated species of 

 Tropaeolum. 



Uredo iridis (Thiim.) forms narrowly elliptical pustules on 

 both surfaces of iris leaves. Mass of spores chestnut colour. 

 Spores almost globose, rarely pear-shaped, rough, brown, 

 30-35 x 20-25 I'- This is distinct from the uredo form of 

 Puecinia iridis. 



Uredo quercus (Brom.) forms small rounded pustules, 

 yellowish, then orange, on the under side of the leaves of 

 young oaks. Spores nearly globose, rough, orange-yellow, 

 15-25 X 12-15 /' 



AECIDIDM (Pers.) 



Peridium cup-shaped, rarely cylindrical, margin often 

 revolute and torn, aecidiospores produced in chains, sub- 

 globose, usually globose. 



Pine cone fungus {Aecidium strobilinum, Rees) forms im- 

 perfectly developed cluster-cups on the inner surface of the 

 carpellary scales or bracts of cones of the Norway spruce 

 {Abets excelsd). A few cups are sometimes also present on 

 the outer surface of the scales. The mycelium of the fungus 

 destroys the (lowers. 



The aecidia are brownish, hemispherical, or polygonal 

 from mutual pressure, numerous, and often covering the inner 

 surface of the scales, opening in a circumscissile manner, 

 spores 18-35 X 16-22 /x, ^P' s P ore hyaline, contents brownish 

 rufous, then paler. 



