SOLANACE^ 565 



produce fertile flowers. Hence while the presence of round 

 poUen grains seems to be necessary to the production of fruit, 

 their presence by no means assures that the ovary will be 

 formed or fruit produced. The ovary consists of two carpels 

 with numerous ovules in each locule. 



Opening of Flower and Pollination. — The anthers are 

 mature at the same time that the stigmas are receptive. The 

 flowers have been found to open between 5 and 6 o'clock 

 a.m. The pollen is usually shed on the second day of bloom- 

 ing, and at this time, the pistil is most receptive. The an- 

 thers open at the top by a pore and, in some cases, split for a 

 short distance. The pollen is carried by the wind. The 

 flowers produce no nectar and are not visited by insects to 

 any extent, although several species of insects have been re- 

 ported as visiting the flowers. East concludes from obser- 

 vations of his own (and of others) that self-fertilization is 

 natural to the species. The flowers wither about the fourth 

 day, in the profuse-seeding varieties. 



Some writers report that fragrance is correlated with pollen 

 yield, but East says he found no noticeable fragrance in 

 American varieties. It is commonly thought that potatoes 

 do not fruit as freely now as formerly, due to the fact that 

 large production of tubers has caused a degeneracy in seeding 

 power. While many of the varieties seldom bloom, and more 

 rarely set seed, some of the best varieties bloom freely and 

 under proper conditions set seed. Eraser says, as a result of 

 working with 300 varieties', many of which were grown for 

 several years, that it is seldom that a variety will not bloom 

 at some time in its life and, furthermore, he found that many 

 of the heaviest yielding varieties bloomed as freely as those 

 of less value. 



In many varieties, the flowers do not open. In the Pearl 

 variety, Fitch finds that tuber productiveness "is universally 



