SUPERNUMERARY CARPELS IN COTTON BOLLS. 1 



By Rowland M. Meade, Scientific Assistant, Crop Acclimatization and Adaptation 



Investigations. 



DISCOVERY OF THE ABNORMALITY. 



An examination of a large number of bolls from several varieties of 

 cotton grown at Lanham, Md., in 190S, revealed an interesting abnor- 

 mality. An early frost had destroyed the leaves, but the stalks and 

 bolls were in the normal green condition. Many bolls had reached 

 maturity, but none had opened naturally, so it was necessary to 

 make all observations in artificially 

 opened bolls. 



In its simplest form the abnor- 

 mality consisted of a solid, elon- 

 gated, whitish body, developed in 

 the center of the boll between the 

 placentae. (See fig. 1.) 



In many instances, however, this 

 body was divided into from two to 

 five longitudinal compartments, re- 

 sembling miniature locks, which 

 inclosed rudimentary ovules. In 

 some cases it extended nearly the 

 entire length of the boll, but was 

 always unattached except at the 

 base. Although the abnormalities 

 observed at Lanham were poorly 

 developed, the longitudinal com- 

 partments with the inclosed rudi- 

 mentary ovules warranted the 

 belief that they might be regarded 

 as supernumerary carpels. 



In some respects this abnormal- 

 ity resembles that found hi the navel orange. There is a difference, 

 however, in that the supernumerary carpels of the cotton boll develop 

 at the base of the placentae, while in the orange they are produced 

 at the opposite end of the fruit. 



Fig. 1. — Supernumerary carpels between the pla- 

 centae oj a green cotton boll. From Glendale, 

 Cal. (Natural size.) 



» Issued Feb. 1, 1913. 



[Cir. Ill] 



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