GAMOPETALOUS COROLLAS. 



205 



of the Pink tribe (figs. 305, 314); the ahinaceous, where the claw is 

 less narrow, and there are distinct spaces between the petals, as in 

 some species of Chickweed ; cruciform, having four petals, often un- 

 guiculate, placed opposite in the form of a cross, as seen in Wall- 

 flower (fig. 315), and in other plants called cruciferous (crux, a cross, 

 and fero, I bear). 



Ieeegulae Polypetalous Ooeollas.— The most marked of 

 these is the papilionaceous (fig. 316), in which 

 there are five petals ; one superior (posterior), e, 

 placed next to the axis, usually larger than the 

 rest, and folded over them in aestivation, called 

 the vexillum or standard ; two lateral, a, the ate 

 or wings ; two inferior (anterior), partially or 

 completely covered by the alse, and often united 

 slightly by their lower margins, so as to form a 

 single keel-like piece, h, called carina, or keel, 

 which embraces the essential organs. This 

 corolla occurs in the Leguminous plants of Britain, or those plants 

 which have flowers like the pea. Among the irregular polypetalous 

 corollas might be included the orchideous (fig. 

 317), although it is really the perianth of 

 a Monocotyledon. This perianth consists of 

 three outer portions equivalent to the calyx, 

 and three inner .parts alternating with them, 

 constituting the petals. The latter are often 

 very irregular, some being spurred, others 

 hooded, etc. ; and there is always one, called 

 the labellum or lip (Fig. 317 I), which pre- 

 sents a remarkable development, and gives rise 

 to many of the anomalous forms exhibited by 

 these flowers. 



Ebgulae Monopetalous oe Gamopbtal- 

 ous Ooeollas. — These are sometimes campanu- 

 late or hell-shaped, as in Campanula rotundifolia 

 (fig. 318) ; infundihuliform or funnel-shaped, 

 when the tube is like an inverted cone, and 

 the limb becomes more expanded at the apex, 

 319); hypocrateriform or salver-shaped, when 



as in Tobacco (fig. 

 there is a straight 



tube surmounted by a flat spreading limb, as in Primula (fig. 



Fig. 316. Irregular polypetalous corolla in the papilionaceous flower of La,tliyrus 

 odoratus. Sweet-pea. e, Calyx, e, Vexillum or standard, a. Two alee or wings. &, 

 Parina or keel, formed of two petals. Fig. 317. Flower of Twayblade (Listera ovata), seen 

 in front, showing a large bifid labellum, I, whieli is different from the other five divisions of 

 the perianth. The divisions of the perianth are in two rows of three each. The essential 

 organs of reproduction are placed on a column opposite the labellum. The perianth is 

 irregular polyphyllous, and is denominated Orchideous. 



