1890.] occurring in the Neighbourhood of Simla. 93 



CHRYSOMYXA, Unger. 



LEPTOCHBYSOMYXA, Schroter. 



1. Chrysomyxa Himalense, Barclay. 



On Rhododendron arhoreum, Sm. 



A detailed description of this fungus will be found in the " Scienti- 

 fic Memoirs by Medical Officers of the Army of India," Part V. It is 

 an extremely conspicuous parasite, since it gives rise to witches' brooms 

 on the host, and is very abundant. The fructification of the fungus may 

 be seen from early spring to the end of May. Tiiis has its seat especi- 

 ally on the petioles and along the midribs a short distance into the leaf 

 blade. When ripe the fruit bodies, which are orange red, clothe 

 the petioles so densely as to hide it completely. Each separate fruit 

 body is club-shaped. The expanded upper part measures on an average 

 2 m.m. in diameter, and the whole about 1'5 m.m. in length. These 

 fruit bodies are also occasionally found on the main axis of shoots and 

 as isolated groups on the leaf blade. In a moist atmosphere they be- 

 come pure yellow from rapid sporidial formation. These fruit bodies 

 are found only on the leaves and stems of the previous year's growth ; 

 never on the newest. The shoots attacked are dwarfed in growth, and 

 bear smaller leaves than normal. There are no uredospores. 



Localised attack of the leaf blade is not common. When it occurs, 

 always on leaves of the previous year's growth, small patches are formed 

 reddish brown above with a cluster of about 25 fruit bodies on the lower 

 surface. The leaf blade at such places is very slightly thickened. 



The mycelium in the stem is perennial. It is of the usual cha- 

 racters, contains an abundance of orange red oil globules and forms 

 haustoria. 



The fruit body consists of four parts : (a), the primary lowermost 

 stalk cells, forming the stalk of the club-shaped fructification : (5), a 

 group of large central cells, three to four in each row, usually forking, 

 and forming the main part of the expanded club end of the fruit body : 

 (c), secondary stalk cells, branches of the last, which give rise to pro- 

 mycelia : and {d), the promycelia proper, measuring about 50/a in 

 length by 10/u. in breadth, and dividing into four cells, each of which 

 produces a sporidium at the end of a narrow sterigma. The sporidia 

 are round or oval, orange red, and measure from 9/x in diam. to 12 X 

 lO/x. The sporidia are thrown off forcibly as in the case of C. Ixhodo- 

 dendri (D. C.). 



