16 



ARRANGEMENT OF PARTS IN THE COTTON PLANT. 



ARRANGEMENT OF THE INVOLUCRAL BRACTS AND BRACTLETS. 



Each flower bud of the cotton plant is protected by an involucre 

 composed of three specially reduced and modified leaf-like organs, 

 technically called bracts. Inside the involucre, between the bracts 

 and the bud proper, still smaller leaf-like organs, the so-called 

 bractlets, may occur. Both the bracts and the bractlets give indi- 

 cations of regular arrangement. 



Two of the bracts are of equal size and are often appreciably larger 

 than the third. The small bract is always borne on the side of the 

 flower that faces outward, toward the end of the branch. (Fig. 3.) 

 Bractlets are most likely to be associated with this small bract. If 

 only two bractlets are present, as frequently happens, they stand at 



either side of 

 this small outer 

 bract. In the 

 Kekclii cotton 

 and other Cen- 

 tral American 

 types the bract- 

 lets often occur 



Fig. 3.— Diagram showing the relation of parts in the cotton flower, 

 and calyx teeth natural size.) 



(Bracts 



in pairs, alter- 

 nating with the 

 bracts, though it 

 is rather unusual 

 to find a com- 

 plete set of six 

 bractlets. 



Wlien a fourth 

 involucral bract 

 occurs, it devel- 

 ops at one side of 



the smaller bract, the side that is toward the leaf of the same node. 

 This additional fourth bract has always been found to be smaller 

 than the third and is even more likely to be accompanied by bractlets. 

 The lacinise, or teeth, of the younger bracts are often bent or 

 twisted in one direction and overlap those of another bract, completely 

 inclosing the young bud. (Fig. 4.) At one node the laciniae twist in 

 one direction and at the next the direction is reversed. This twisting 

 is opposite in direction to that of the internode which bears the 

 flower and in the same direction in which the petals of the same 

 flower overlap. 



ARRANGEMENT OF THE LOBES OF THE CALYX. 



The calyx of the cotton flower is usuallv very small, the usual func- 

 tion of the calyx, to i^iotect the 3'oung bud, liaving been assumed by 

 the much larger involucral bracts. The calyx forms in most kinds of 



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