466 
Pole Evans . — The Cereal Rusts . 
Figs. 31 and 32. Longitudinal sections of stomata, showing infections with characteristically 
shaped sub-stomatal vesicles of P. Symphyti-Bromorum. 
Fig. 33. Small portion of a typical hypha of P. dispersa with its nuclei. The tip of the hypha 
has just become transversely septate, preparatory to the formation of a haustorium. From a five- 
day culture. 
Fig. 34. Typical haustorium of P. dispersa. 
Figs. 35 - 7 . Uredo infection of P. simplex on Barley. 
Figs. 38 and 39. Uredo infection of P. coronifera on Oats. 
Figs. 40-3. Uredo infection of P. Sorghi on Maize. 
Fig. 35 . Four-dav culture of P. simplex on Barley, showing sub-stomatal vesicle with its 
infecting hyphae. The first transverse wall in the vesicle is just beginning to be formed. 
Figs. 36 and 37. Both from the margins of Uredo pustules of P. simplex on Barley, taken from 
an outbreak in the field (and not artificially inoculated). 
The sub-stomatal vesicles have become empty and divided by transverse septa. The hyphae are 
beginning to lose their protoplasm and become septate. 
Figs. 38 and 39. Longitudinal sections of Oat leaf showing infection phenomena of P. coronifera. 
A single transverse septum is formed in each sub-stomatal vesicle, which gives rise to an infecting 
hypha from each end. Both five-day cultures. 
Fig. 40. Infection of Maize leaf by P. Sorghi. The sub-stomatal vesicle is full of protoplasm, 
and not yet fully developed. 
PLATE XLIII. 
Figs. 41 and 42. Older infections of Maize leaf by P. Sorghi. Four-day cultures showing 
characteristically shaped vesicles with their infecting hyphae and haustoria. 
Fig. 43. Infection of Maize leaf by P. Sorghi , showing shape of sub-stomatal vesicle in 
transverse section. 
Fig. 44. Typical haustorium of P. simplex on Barley. 
Fig. 45. Haustorium of P. dispersa on Rye. 
