135 



tissues of the plant attacked, and as the latter grows, the 

 mycelium grows along with it, without, however, so far as cne 

 can see, injuring the plant in any way. The presence oi the 

 fungus is indeed only made manifest to the ordinary observer 

 shortly before the time of harvest. The hyphae of the fungus 

 entering the flowers feed on and destroy the substances which 

 should have been devoted to the development of the grain, and 

 eventually, instead of the ripe corn, we find the soot-like masses 

 of resting spores. 



Ustilago Maydis is common on maize in India and is easily 

 recognised by the boil-like swellings, or blisters, which may occur 

 on leaves, stem, flowers, or fruit heads. These blisters, .which 

 may attain the size of one's fist, contain the spores and, when the 

 latter are ripe, the blisters burst and the dark-coloured spores 

 escape. The maize heads are usually attacked and the grain, 

 is consequently destroyed. 



121. Uredinaceae. Hyphse are,. ,. 



septate. Sexual reproduction doubtful. The fungi included in 

 this group are characterised by their polymorphism. Several 

 kinds of spores are usually produced by them and their com- 

 plicated life-history will be best understood from the detailed 

 account of Puccinia graminis given below in Part V. 



Owing to the frequent development of masses of orange- 

 yellow, or rust-coloured, spores, which give the appearance of 

 rusty streaks, or patches, on the leaves of the plants 

 attacked by them, these fungi, in contradistinction to those of 

 the previous group, are popularly known as rusts. A very 

 large number of these fungi occur on the leaves of our Indian 

 forest trees and shrubs, but, as a rule, they are not very 

 injurious and are, consequently, not of great importance. Only 

 a few of those which are most noticeable in the forest of the 

 North- West Himalaya will be mentioned here. 



One of the most remarkable is that known as Bardaydla 

 deformans (formerly named Aecidium Thomsoni) which causes 

 the orange-red tassels so frequently seen in the forests of 

 Jaunsar-Bawar on the spruce, Picea Morinda (see Plate XV, 

 Fig. 1 (a) and (b) ). Only the current year's shoots are attacked, 

 these being "stunted, thickened and densely covered with 

 curved needles." Every needle on the attacked shoot is affected 

 and they afford a striking contrast to the straight-, healthy 

 needles. The masses of orange-red spores (teleuto-spores) 

 form " two continuous flattened beds on the upper surface " 

 and two smaller beds on the under-surface of the needles. 

 When young, the tassels emit a disagreeable odour. The 



