■ HlKATSUKA: Sll'DIFS ON IIIE FLAX RlST S 



the single nucleus in its spermatioplioies divides successively to form the nuclei 

 for a number of spcrmatia wliich are abstricted from the elongated finger-like 

 tip of the spermatiophorc. Fkomme says that these characters of the spermatio- 

 phore may furnish a further basis for use in the classification of the Uredinales, 

 and tlie writer agrees with this opinion. 



The spermatia are much smaller than the other spore-forms, measuring 3-- 

 to 5.4 f^ by 2.2 to 4.6 It. They are oval or ellipsoid in shape and enclosed 

 in a very thin wall. The cytoplasm is finely granular with apparently no re- 

 serve materials. The nucleus is relatively large in size. 



B. Aecidial stage. 



1. Aecidiuin. The aecidia are mostly on the under surface of the coty- 

 ledonous and foliage leaves, but rarely on the upper surface or on the stems, 

 scattered, round or oblong, flatly pulvinate, 230 to 450 /i in diameter, and 

 orange-yellow in colour. They develop under the epidermis and then rupture 

 it at maturity, but without any peridium and paraphyses. It is of the Caeoma- 

 type of aecidium, one of the characters of the genus Melmiipsora. 



2. Aecidiospore. The aecidiospores are variable in shape, globose, ellip- 

 soid or somewhat polygonal. They contain yellowish orange pigment and 

 measure 17.6 to 27.2 /i by 16.2 to 24.0/^ in diameter. The epispore is colour- 

 less, thin and verrucose, without any distinct germ-pores. 



C. Uredo stage. 



1. Uredosorus. The uredosori arise from the mycelia resulting from the 

 infection with the aecidiospores, and also later on from the infection by the 

 first-formed uredospores. They occur on both sides of the foliage and cotyle- 

 donous leaves, and also on the stems, branches and inflorescences. They are 

 produced under the epidermis, which is soon ruptured thus exposing the spores. 

 The sori are round or oblong, scattered or clustered on the leaves, generally 

 in circular groups up to about 4 mm. in diameter and elongated on the stem, 

 up to about 2 mm. across, powdery, prominent, and bright orange-yellow in 

 colour. The sori are indefinite in extent, having numerous paraphyses inter- 

 mixed, and also a parenchymatous peridium in their younger stage. 



2. Uredospore. The uredospore is singly borne upon a long stalk which 



