6 A CHAPTER TO STUDY. 



Labiate : when there is an apparently two-lipped division of 

 the parts. In this form of corolla usually two petals grow to- 

 gether and make the upper lip ; the remaining three petals join 

 together and form the lower lip. These divisions appear mostly 

 as lobes, and it is not always noticed that the flowers are of five 

 lobes instead of two. (FiG. 19.) 



STIGMA 



FIG. 24. FIG. 25. FIG. 26. 



When the petals are not grown together but are wholly sepa- 

 rate, the corolla is said to be polypetalous. Different forms 

 are : 



Rosaceous : when the petals are distinct and without claws, 

 as in the rose. 



Cruciferous': when there are four clawed petals in the form 

 of a cross. (FiG. 20.) 



Papilionaceous, or butterfly-shaped. (FiG. 21.) Such 

 flowers are usually described in three parts : the banner, or 

 standard, which is the large upper petal ; the wings, or the 

 two side petals, and the two anterior petals that, commonly 

 united in a shape something like the prow of a boat and enclos- 

 ing the reproducing organs, are called the keel. (Fio. 22.) 



