

FIELD CROPS. 7. r >7 



the level in the reservoir constant. Since the plants were 2 ft. high a daily a\ 



of 3 lbs. of water was used per stalk, u bich is equivalenl to a rainfall of 1 in. everj 



7.1 -lays. 



What is an ear of corn? E.G. Montgomery I Pop. Sci. Mo., 68 (1906) t No, t t pp. 

 65-6$, figs. 14). — The observations made suggesl to the author thai corn and teosinte 

 may have had a common origin, the progenitor of these plants probably being a Large 

 much-branched grass, cadi branch being terminated by a tassel-like structure bear- 

 ing hermaphrodite fl< >wers 



In the process of evolution the cluster of pistillate spikes in teosinte is considered 

 as having developed from the Lateral branches of a tassel-like structure while the 

 corn car developed from the central spike It is further indicated as probable thai 

 the centra] tassel, as evolution progressed, produced only staminate flowers while 

 the lateral branches produced only pistillate flowers, and that this differentiation was 

 accompanied by a shortening of the internodes of the Lateral branches until they 

 were entirely inclosed in the Leaf sheaths, as is the case with en ear of corn. 



Weevil-resisting- adaptations of the cotton plant, < ). F.Cook i U. S. Bept. Agr., 

 Bur. Plant Indus. Bui. 88, pp. 87, pis. 10). — This bulletin contains an accounl of obser- 

 vations and experiments Bhowing that some of the varieties of the cotton plant have 

 definite weevil-resisting characters. 



One of the firsl results in this Line of work was the discovery of the weevil-eating 

 kelep. It appears from these observations, however, that the usefulness of theinseel 

 is not Limited to weevil destruction, but that by making a regular field culture of cot- 

 ton possible in regions infested with the weevil it has contributed to the develop- 

 ment of weevil-resisting characters in the plant. These characters are regarded as 

 modifications in the plant for the purpose of self-protection againsl its inseel enemies. 



The general protective characters, the involucre as a protective structure, and the 

 protection of the bolls and of the seed are discussed at some Length. The extrafloral 

 nectaries of the cotton plant are described and their functions as insect-attracting 

 devices pointed out. A description of the behavior of the parasitized buds is also given. 



I discussions on the cultural value of Kidney cotton, the uature and causes of weevil- 

 resisting adaptations, and the improving of varieties by conscious and unconscious 

 selection are presented. The different adaptations are classified as avoiding weevils, 

 excluding weevils, attracting the kelep, and preventing the development of weevil 

 larva'. The adaptive characters of different types of cotton, including Kekchi. Etabi- 

 nal, Pachon, San Lucas Sea Island, Kidney, and upland cottons, are also listed. 



In an experiment conducted in Guatemala it was found that plants of Kekchi cot- 

 ton cultivated on the United States system were much more robusl and compact than 

 the plants grown by the Indian- in more crowded fields. Considerable variation in 

 this cotton was observed even among plants mown from seed raised by the same 

 Indian, and this fact is considered as giving promise of securing strains having the 

 special characters required in the United States. On the other hand it was found that 

 Guatemalan conditions cause variation in United States varieties. King lost mosl 

 of its distinctive characters and broke up into a variety of types and in general 

 receded in earliness. Allen, Sea Island, and Egyptian varieties became more preco- 

 cious ami in some instances gained in vigor and productiveness. Kekchi cotton in 

 Texas grew Large and rank but began to fruit toward the end of July, giving promise 

 of successful seed production under the prevailing climatic condition-. 



A test of Kekchi cotton was made at Lanham, Md., in 1905, and while this local- 

 ity is at the northern limits of cotton cultivation, this variety produced more mature 

 plants than any of the domestic and foreign varieties compared with it. It also 

 remained more constant in Maryland than did King in Guatemala. When light 

 frosts occurred in this locality about the end of Septemberthe Kekchi plants did 



not suffer more than the American upland varieties. I'achoii cotton from western 

 Guatemala grew from 52 to 79 in. high and produced no buds at Victoria, Tex., 



