CH. IX] TYPES OF COROLLA 77 



alike and arranged cross-wise, is typical of nearly the 

 whole of the large Order (Cruciferse) to which it gives 

 the name, though it is found in other cases also, e.g. 

 Chelidonium, Poppy, Spindle Tree, &c. (Fig. 11). 



The Rosaceous corolla (Fig. 43) of five similar spreading 

 shortly-clawed petals, so arranged that two are entirely 

 outside, two wholly inside, and the other with one margin 

 inside, and one outside in the bud, is again characteristic 

 of many flowers of the Natural Order Rosaceae besides the 

 Rose, Strawberry, Potentilla, &c. 



The Papilionaceous corolla (Fig. 44) is zygomorphic, 

 and consists typically of a large standard wholly exterior 

 and superior ; two lateral ivings with their upper margins 

 beneath the standard and their lower ones outside the 

 keel, a boat-like structure formed of two long petals joined 

 by their lower margins. This form is found in the Bean, 

 Pea, Laburnum, Robinia, Gorse, Whin, Broom, and most 

 other plants of the Natural Order Papilionaceae. 



The Bilabiate corolla is gamopetalous and zygomorphic, 

 and consists of a tube, long or short, and a limb divided 

 into two lips, an upper and a lower one, each lip with its 

 own peculiar markings, incisions, and so forth in the dif- 

 ferent cases. This type again is very characteristic of 

 large groups of plants, though rare in our shrubs and 

 trees ; it is well exemplified by the Dead-nettle, Sage, 

 Rosemary, Honeysuckle, &c. (Fig. 142). 



Other examples of characteristic gamopetalous corollas 

 are, tubular (Tobacco), funnel-shaped (Convolvulus), cam- 

 panulate (Hare-bell), urceolate (Heath), where the inflated 

 belly and narrowed aperture suggest an urn ; rotate, with 

 very short tube and flat, wheel-like, spreading limb, e.g. 

 Pimpernel, Borage, Holly, Elder, Guelder Rose, &c. 



It is not uncommon to find a Ligule at the angle which 

 the limb makes with the claw, as in the petals of Lychnis 



