CHAPTER IX. THE TORUS, CALYX AND COROLLA. 73 



already learned in leaf-description are therefore also applicable, 

 for the most part, in the description of petals. 



Where the petals are not at all united with each other, the 

 corolla is described as choripetalous, or, less correctly, as poly pet '- 

 a Ions. If the distinct petals are four in number and arranged 

 in the. form of a cross, as they are in the Cress family, it is called 

 cruciform ; if the petals are five and short-clawed or clawless 

 and spreading, like those of the wild Rose, it is called rosaceous ; 

 if there are five long-clawed petals, having the claws concealed 

 in the tube of a gamosepalous calyx, as in the Pink, it is called 

 caryophyllaceous, Fig. 280 ; when it is shaped like the irregular 



Fig. 214. Fig. 215. Fig. 216. 



Fig. 214. — Flower of Genista, slightly enlarged, iu front view. 

 Fig. 215 — The same in lateral view. 



Fig. 216. — The petals of the same separated, -r is the I'ejcilluntox standard; y,y' ', the 

 alee or wings, and =, -'. the two petals which compose the carina or keel. 



flower of the Pea or Genista, it is called papilionaceous, Figs. 214. 

 215 and 216; when calyx and corolla each consist of three 

 pieces closely resembling each other in form and color, as in the 

 Lily and Tulip, the flower is called liliaceous ; and when, as in 

 the Orchidaceae, the floral leaves are epigynous, and calyx and 

 corolla are in whorls of three pieces each, and one of the petals, 

 called the lip, has a shape markedly different from the rest, it is 

 called orchidaceous. In flowers like the latter two, where calyx 

 and corolla closely resemble each other, they are commonly not 

 distinguished by separate names, but the two together are called 

 the perianth. 



But the petals very often become more or less united. In 

 this case the corolla is described as gamopetalous. The united 

 portion is called the tube, and the free portion, the limb, as in the 

 calyx. 



A gamopetalous corolla is caled rotate, or wheel-shaped, 

 when the tubular portion is short, and the divisions of the limb 

 Tadiate from it like the spokes of a wheel, as in the corolla of 



