Reed: The mildews of the cereals 381 



sterile. The anthers did not open; in fact, the pollen was im- 

 perfectly developed. 



Carman * ^^^ "' ^^ has also obtained a hybrid between wheat and 

 rye. In 18S2 he placed pollen from rye on the stigma of a white 

 club- wheat. From the seed obtained he was able to grow plants 

 for several generations. In the first year there were eight plants, 

 which yielded good grains. The next year the seed from these 

 eight plants was sown and grew to strong, healthy plants, produc- 

 ing, however, a medley of wheat plants. Some had naked heads, 

 others had long awns of various types, all, however, closely related 

 to wheat. The ninth plant obtained in the first year resembled 

 rye and produced apparently worthless grains. However, when 

 these grains were planted, they gave rise to plants which had a 

 strong resemblance to the parent rye. The plants were much 

 taller than the original wheat plant. In the character of the head 

 there was a close resemblance to wheat. 



In 1888 Rimpau ^ attempted to cross wheat and rye. He 

 took the pollen from the rye and placed it on the stigma of the 

 wheat flower. He obtained one seed, which gave rise to a plant 

 that had long and narrow awns; the haulms were 30 cm. longer 

 than those of the wheat plants, differing especially in the length 

 and narrowness of the ears from the mother parent. The grains 

 secured from these plants were sown in 1890. One plant pro- 

 duced brown, short, sterile heads similar in form to the square- 

 head wheat; two plants had white, fertile heads, similar to the 

 square-head wheat ; the other resembled in character the hybrids 

 of the previous year, having very long, narrow, brown, wheat-like 

 heads, which, however, had the more open flower characteristic 



of the rye. 



As already stated, the seed which I used in my experiments 



came from this original cross by Rimpau. As seen from table 

 XVI, thirteen tests were made, eighteen plants being inoculated 

 with conidia from the rye. Of these plants, nine showed evidences 

 of infection. Six plants had a fairly good growth of mildew, 

 conidia being produced. On the other three, however, only well- 

 ' marked discolored areas appeared. In no case did I obtain the 

 vip^orous crrowth of mildew characteristic of this fungus on the 

 rye plant. 



* A good account of Carman's work is given by Barnard. 2 



