POBMS OF TBE PEBIANTB 



185 



ver; and many corollas are exceedingly irregular. 

 The form of the corolla is most striking and defi- 

 nite in gamopetalous flowers. The important thing 

 to remember, however, is not the name of the 

 form, but the fact that there are multitudinous 

 forms. 



211a. Some of the characteristic forms of corollas are shown in 

 the engravings. Fig. 176, bell-shaped, or campanulate; Fig. 177, 

 salver- shaped ilimb flaring at right angles to the tube); Fig. 178, 



rotate, or wheel-shaped, the limb being 

 nearly circular and the perianth having 

 practically no tube; Fig. 179, tubular- 

 trumpet- shaped, or tubular-inflated (the 

 morning glory is a typical example of a 

 trumpet-shaped flower) ; Fig. 180, labi- 

 ate, or two-lipped (characteristic of the 

 mints); Fig. 181, lipped, or lobed, and 

 therefore irregular flower. Flowers in 

 which the parts or lobes of the calyx 

 and corolla are all alike in shape and 

 size, in the same series, are said to be 

 regular (like Figs. 131, 133, 138, 139, 

 143, 144, 146, 148, 161, 162, 173B, 175, 

 176, 177, 178, etc.); others are irregu- 

 lar (as in Figs. 170, 179, 180, 181). 

 2116. When the parts in all the 

 four series are of the same number, the flower is said to be isom- 

 erous. "Symmetrical" is generally regarded as synonymous with 

 "isomerous," but symmetrical should be used to designate the fact 

 that the parts of the four series are of the same number, or in 

 multiples of the lowest number. That is, the petals may be five, 

 but the stamens ten; in which ease it is assumed that the stamens 

 are in two rows of fives. 



212. In the tulip (Fig. 138) and the lily (Fig. 

 148) there is no distinction between calyx and 



Fig. 182. 



Lily-of-the-valley flower, 

 laid open. 



