FIBER CROPS 



313 



particular, by selection. The plant is cone-shaped, the lower 

 branches about six inches from the ground being longest and 

 next above gradually growing shorter until the top is reached. 

 The leaves are large, three to six inches long, and two to 

 five inches wide. The first ones are entire and somewhat heart- 

 shaped; subsequent leaves are three to five, rarely seven, lobed. 

 The midvein, and sometimes the lateral veins, bears a dark 

 green gland near its base, which may serve as a variety char- 

 acteristic. All vegetative portions of upland cotton are covered 

 with short hairs. 



405. Flowers. The flowers are regular, having five small, 

 united sepals and five large petals. The flowers open at sunrise 



Cotton boll: longitudinal and cross-sections show the arrangement of seeds; the cross- 

 section on the right shows the division into carpels 

 (From photo by Bennett) 



or just before. In upland cotton the petals, when they open, 

 are creamy-white, and in sea island, bright yellow. During the 

 day they turn pink or bright red. The flowers close late in the 

 day, and never open again; hence, if cross- fertilization takes 

 place, it must be during the single day that the flower is open. 

 The corolla falls, but the calyx is persistent, although small 

 and inconspicuous. The young capsule or boll, surrounded by 



