226 THE INFLORESCENCE. 



cles, which have become lateral by the evolution of a branch from 

 an axil below, which takes the direction of the main stem, so as 

 to form an apparent continuation of it. This has been explained 

 on the supposition of the cohesion of the base of an axillary pedun- 

 cle with the stem ; which could well apply only to those cases 

 where the peduncle is in the same vertical line as the leaf beneath. 

 Such peduncles may sometimes come from extra-axillary acces- 

 sory buds, such as those shown in Fig. 133. 



409. In the Linden (see Ord. Tiliacea3) the peduncle appears to 

 spring from the middle of a peculiar foliaceous bract. But this is 

 rather a bractlet, inserted on the middle of the peduncle, and de- 

 current down to its base, just as many leaves are decurrent on the 

 stem (298) in Thistles, &c. 



410. A peduncle which arises from the stem at or beneath the 

 surface of the ground, as in the Primrose, the Daisy, the so-called 

 stemless Violets, &c., is called a radical peduncle, or a SCAPE. 



411. A combination of the two classes of inflorescence is not 

 unusual, the general axis developing in one way, but the separate 

 clusters of flowers in the other. Thus the heads of all the Com- 

 posite (such as Thistles, Asters, &c.) are centripetal, the flowers 

 expanding regularly from the margin or circumference to the cen- 

 tre 4 while the branches that bear the heads are developed in the 

 centrifugal mode, the central heads first coming into flower. 



412. This is exactly reversed in all Labiatse (plants of the Mint 

 tribe) ; where the stem grows on indefinitely in the centripetal 

 mode, bearing axillary clusters of flowers in the form of a general 

 raceme or spike, which blossoms from below upwards ; while the 

 flowers of each cluster form a cyme, and expand in the centrifugal 

 manner. These cymes, or cymules, of Labiata? are usually close 

 and compact, and being situated one in each axil of the opposite 

 leaves, the two together frequently form a cluster which surrounds 

 the stem, like a whorl or verticil (as in the Catnip and Horehound): 

 hence such flowers are often said to be whorled or verticillate, 

 which is not really the case, as they evidently all spring from the 

 axils of the two leaves. The apparent verticil of this kind is some- 

 times termed a VERTICILLASTER. 



413. True whorled flowers occur only in some plants with 

 whorled leaves, as in Hippuris and the Water Milfoil. 



