SUMMARY OF ADAPTATIONS, 78 



ADAPTATION.S TO EXCLVUE WEEVILS. 



1. Involueral bracts grown together at liase. 



•J. Closely appressed margins of invohn-ral bracts. 



3. Margins of involueral Itracts strongly la<-lniate and hairy. 



4. Unusual size and width of involueral bracts. 



5. Calyx produced into slender hairy lacinire. 

 <i. Persistent flowers. 



7. Oil glands (Vl of .very young bolls. 



8. Thick-walled bolls. 



9. Tough linings of boll chambers. 



ADAPTATIONS ATTRACTIVE TO THE KELEP. 



1. Nectaries of leaves. 



2. Large outer nectaries of involucre. 



3. Large inner nectaries of involucre. 



4. Bractlets subtending inner nectaries. 



5. Continued secretion of nectar. 



0. Hairy stalks and leaf stems. 



7. Dwarf, compact habits of growth. 



ADAPTATIONS TO PREVENT DEVELOPMENT OF WEEVIL LARV.E. 



1. Shedding of weevil-infested buds. 



2. Proliferation of internal tissues of buds. 



3. Proliferation from the walls of the bolls. 



4. Absence of oil glands over dissepiments. , 



5. Growth of lint on seed. 



6. Compacted seeds (Kidney cotton). 



7. Lint confined to outer end of seed (San Lucas Sea Island cotton). 



ADAPTIVE CHARACTERS OF DIFFERENT TVPLS OF COTTON. 



The third st;\ndpoint for viewing the adaptive characters is that 

 of the dilferent types of cotton. All varieties share, to some extent, 

 the older adaptive features, but the special characters are accentuated 

 in different degrees in the various types. Our study has been directed 

 toward the Kekchi variety, both on account of its relation to the 

 keleps and because it has seemed to possess by far the largest series 

 of adaptive features. But now that the existence of adaptations of 

 practical value has been ascertained it will be necessary to canvass 

 the field thoroughly. 



ADAPTATIONS OF KEKCHI COTTON. 



An enumeration of the adaptations of the Kekchi cotton is scarcely necessary, 

 because that variety has nearly the whole series and most of them in a more 

 accentuated form than the other types thus far studied. The few" exceptions 

 are noted below. 



ADAPTATIONS OF RABINAL COTTON. 



1. Prompt bearing after cutting back. 



2. Very hairy stalks, leaf stems, and involueral bracts. 



3. Closely appressed margins of involueral bracts. 



4. Involueral bracts gi'own together at base. 



