MISCELLANEOUS NOTES. 109.5 



must still remain doubtful. It is thought desirable, in the meanwhile^ 

 to describe in detail the fungus as it occurs in the Indian specimens. 



The rust is very common on the Castor plant in the Poona, Belgaum and 

 Dharwar districts of the Bombay Presidency. It is remarkable that it is 

 practically absent from Gujerat, though the varieties commonly grown 

 there are by no means immune to this disease. Plants of all the common 

 Gujerat varieties were grown for experimental purposes on the Poona 

 Agricultural College Farm and these all got the rust. 



This rust usually appears between the months of November and February 

 on Castor sown in June as an annual crop. But it has been observed as 

 early as September on some Castor plants more than a year old in the 

 Ganeshkhind Botanical Garden, Kirkee, and from the appearance of the 

 leaves which were entirely covered with pustules, the rust had presumably 

 been there all the svimmer. The attack is severest in January when 

 practically every leaf of the plant is thickly covered with pustules, and 

 clouds of spores are blown off from them on shaking the plant. 



The orange yellow, powdery pustules (Uredosori) are confined to the leaf 

 and occur chiefly on the lower surface, though very rarely they are met 

 with on the upper surface also. They are indicated on the upper surface 

 by minute roundish yellow spots. They occur in large numbers and not 

 infrequently show an arrangement in concentric rings (Fig. 1), and they 

 often run together. In severe cases this arrangement in rings is lost and 

 the entire surface is covei-ed thickly with pustules. 



A transverse section of the leaf through a young pustule shows that the 

 Uredo spores are first covered entirely by a peridium consisting of fungus 

 tissue of polygonal cells. (Fig. 2). When mature they become exposed by 

 rupture both of epidermis and peridium, which latter can still be seen as a. 

 layer underlying the epidermis. (Fig. 3). The spongy parenchyma below the 

 epidermis is more or less completely occupied by the hypha) of the fungus, 

 which form a sort of a cushion on which the spore-bearing hyphse arise. 

 The spore-bearing hyphse separated by manipulation present a characteris- 

 tic appearance. They are curiously branched and, as a rule, only two of 

 these branches bear spores, the oldest spore being always at the top. 

 (Fig. 4). The other branches are slender, pointed and sterile. Further the 

 Uredo spore bearing hyphte are intermixed with stout, club-shaped, para- 

 physes, generally colourless but occasionally the swollen heads showing 

 orange colour. (Fig. 5 a &, b). In the last case the paraphyses are easily 

 distinguishable from the spore-bearing hyphse by the perfectly smooth out- 

 line of their swollen heads. In mature sori the paraphyses generally project 

 beyond the level of the spores. 



The Uredo spores are globular or elliptical, echinulate and with orange 

 contents. When examined fresh in distilled water it is possible to dis- 

 tinguish between two kinds of Uredo spores, one with thick walls and the 



