FUNGOID PESTS OF CULTIVATED PLANTS. 231 



Spuing Corn Mildew. 

 Puccinia Rubigo-vera (DC), PI. XXII. fig. 4. 



This corn mildew occurs on Wheat, Eye, Barley, Oats, and several 

 grasses. The cluster-cups are supposed to occur on Anchusa, Pulmonaria, 

 Borago and other genera of Boraginacece. 



The uredo pustules are elliptical, oblong, or linear, and were originally 

 known as Uredo Bubigo-vera. The uredospores are globose or ellipsoid 

 (20-32 x 17-24/j), externally rough, on short pedicels, orange-red. 



Teleutospores in small elliptical pustules, or linear and confluent, 

 black, for a long time covered by the epidermis ; spores oblong or clavate, 

 flattened at the apex, or laterally apiculate, lower cell attenuated down- 

 wards into the short pedicel (26-80 x 16-24//) even, chestnut-brown. 



Known over the greater part of Europe, in Asiatic Siberia, Ceylon, 

 North and South America. 



This is called "spring rust" because the uredo generally appears 

 between March and May. It is not so well known or so devastating as 

 the summer rust which precedes Puccinia graminis, and does not appear 

 until June or July. 



Ploivr. Brit. Urecl. p. 167 ; Sacc. Syll. vii. 2194 ; Smith, Field Crops, 

 p. 135, figs. 62-69 ; Mass. PL Bis. p. 249 ; Cooke, M. F. p. 202 (stramims). 



There is a supposed species (Puccinia glumarum) found on Wheat, 

 Barley, Oats, &c, in which the spores are developed on the leaves and 

 chaff, considered by others as a variety of the above. 



Crown Rust. 

 Puccinia coronata (Corda), PL XXII. fig. 5. 



This mildew or rust is found on the leaves of Barley, and on various 

 kinds of grasses, such as Alopecurus, Festuca, Aim, Lolium, &c, but the 

 cluster-cups are reputed to be developed on the leaves, petioles, &c, of 

 different species of Bhamnus, and will consequently appear as a disease of 

 the Buckthorn. 



The pustules of the uredo are lance-shaped or linear, sometimes con- 

 fluent, uredospores irregularly globose or elliptical (19-28 x 16-2Lu), 

 externally rough, tawny-orange. 



The pustules of the teleutospores are oblong, or linear, or confluent, 

 for some time covered by the epidermis, dark brown. Teleutospores club- 

 shaped, flattened at the apex, darker, and toothed, the acute teeth crown- 

 ing the spore (35-60 x 12-21), a little constricted at the division of the 

 cells, smooth, pale brown, with a short and rather thick pedicel. The 

 crowning of the teleutospores is very characteristic. 



Known in France, Belgium, Germany, Finland, Switzerland, Austria, 

 Italy, Portugal, North America, and South Africa. 



It is occasionally met with on Wheat, Barley, and Rye, but less com- 

 monly than on grasses. 



Sacc. Syll. vii. 2192 ; Mass. PL Dis. p. 249 ; Cooke, Edbk. No. 1465 ; 

 Cooke, M. F. p. 203, figs. 60-62 ; Plowr. Brit. Ured. p. 164. 



