B6 MORPriOLOGY 



petiole-like portion called claw, as in Mustard and 

 Garden Nasturtium. 



The corolla, like the calyx, may be free or poly- 

 PETALOUS, as in Poppy, shial-kanta, and Radish; or 

 it may be coherent or gamopetalous, as in Datura, 

 juin {/asminum), sheuli {Nyctanthes), and kalmi- 

 shag. Whether poly- or gamopetalous, the corolla 

 is said to be regular or irregular according as the 

 petals are equal or unequal in size and form. In 

 practice a flower is said to be regular or irregular 

 according to the regularity or irregularity of the 

 petals, irrespective of the regularity or irregularity 

 of the calyx or other whorls. 



The commonly occurring forms of polypetalous 

 regular corolla are (fig. 82): (i) cruciform — a, when 

 four petals, each with a claw, are inserted diagonally or 

 crosswise on the thalamus, as in Mustard and Radish; 

 (2) ROSACEOUS, when the petals are spreading and 

 inserted on the thalamus with a broad base, as in 

 Rose; (3) caryophyllaceous — b, when there are 

 five petals with long claws and spreading limbs, as in 

 Pink and amrul. A polypetalous irregular corolla has 

 one specially noticeable and common form, namely, 

 papilionaceous — c (see fig. 97), when there are five 

 petals of which one is considerably larger than the 

 rest, posterior and exterior, and is known as vexillum 

 or standard or banner; two lateral and smaller ones 

 called AL/E or wings; and two anterior ones called 

 KEEL or CARINA, as in Pea, bak {Sesbania grandi- 

 flora), and in fact in all the Pulse family of plants. In 

 all flowers with papilionaceous corolla the posterior 

 and exterior vexillum wholly encloses all the other 

 petals in the bud state. 



The common forms of gamopetalous regular corolla 

 are: (i) tubular — d, as in the disk florets of surya- 



