132 



COMPOUND ORGANS OP PLANTS. 



Fig. 38. 



more or less elongated tube of the corolla. The rotate or 

 wheel-shaped, as in the Myosotis palustris or forget-me-not, 

 which is a salver-shaped corolla without a tube, or with a very 

 short one. The tubular or tube-shaped, as in the Caprifolium 

 or honey-suckle, where the limb is not developed and the 

 corolla is cylindrical or tubular throughout its entire length. 

 The urceolate or urn-shaped, as in Vaccinium macrocarpon, the 

 American cranberry, in which there is scarcely any limb, and 

 the tube is narrowed at both ends and expanded in the middle. 

 Irregularities in the form of monopetalous corollas are 

 produced by differences in the degrees of cohesion amongst the 

 petals. The principal forms of irregular monopetalous corollas 

 are : the labiate or lipped, (from labium, a lip,) (Fig. 89, a,) 

 in which the tube is more or less elongated, the throat open 

 and dilated, and the limb divided traversely in such a way as 

 to produce an upper and lower portion called the labia or lips, 

 with a hiatus or gap between them, like the mouth of an ani- 

 mal. The upper lip is usually composed of two petals, as the 



