ARRANGEMENT OF CALYX LOBES. 



n 



cotton merely a shallow cup around the bases of the petals. The 

 margin of the cup is more or less divided or produced into five lobes, 

 sometimes short and broad, sometimes long and pointed. The 

 assumption that these lobes represent as many sepals or bracts of 

 some ancestral relative is warranted by their position and by the 

 fact that a transparent line is also sometimes to be seen, extending 

 from the sinus between two lobes to the base of the calyx. 



Seldom, if ever, is a calyx found with lobes of uniform size. Usu- 

 ally there are two large lobes, two small lobes, and one of intermediate 

 size. In the Egyptian cotton and in some of 

 the Asiatic species, calyxes are found with the 

 margin almost evenly truncate, but it is 

 usually possible to distinguish the five lobes 

 and to see that they are of unequal size. 



One of the small lobes stands between the 

 two large lobes and is alwaj^s on the outer 

 face of the calyx, that is, opposite to the small 

 outer bract of the involucre. (Fig. 5.) The 

 other small lobe is between one of the large 

 lobes and the intermediate lobe, but it ma}" 

 be on either side of the intermediate lobe. 

 The position of the second of the small lobes 

 with reference to the intermediate lobe has a 

 constant relation to the twisting of the other 

 parts of the flower. If the petals twist to 

 the right the intermediate lobe is at the right 

 of the small lobe, and vice versa. These rela- 

 tions can usually be ascertained mthout 

 much difficulty, though abnormal calyxes are 

 occasionally found, especially in connection 

 with irregularities in the petals and other 

 floral organs. 



In view of the fact that organs of inter- 

 mediate form are often found, it is not un- 

 reasonable to consider the so-called calyx as belonging to tne same 

 series of modified leaf organs as the outer involucral bracts. In 

 other words, the so-called calyx may be looked upon as the inner 

 ' involucre rather than as a true calyx. This view seems to give a 

 better understanding of the arrangement of parts. It would explain, 

 for example, the further fact that the smallest lobe, on the outer 

 (distal) side of the calyx, seems to stand directly opposite to the 

 small outer bract of the involucre, whereas none of the other lobes 

 appears opposite to the bracts. The small outer involucral bract would 

 commence and the smallest lobe of the calyx would complete one whorl 

 or series of eight leaves in the usual system of leaf arrangement. 



222 



Fig. 4.— Brads of Upland cotton 

 Inclosing bud, showing twisted 

 teeth. (Natural size.) 



