142 



THE FLOWER 



Umbfxlets. When the umbellets are subtended by an involucre, 

 this secondary involucre is called an Involucel. 



302. A compound raceme is a cluster of racemes racemosely ar- 

 ranged, as in Smilaclna i-acemosa. A compound corymb is a corymb, 

 some branches of ^Yhich branch again in the same way, 

 as in Mountain Ash. A compound spike is a spioately 

 disposed cluster of spikes. 



303. A Panicle, sucli as that of Oats and many 

 Grasses, is a compound flower cluster of a more or less 

 open sort which branches ^ith apparent irregularity, 

 neitlier into corymbs nor racemes. Figui'e 2i9 repre- 

 sents the sim^ilest panicle. It is, as it were, a raceme 

 of which some of the pedicels have branched so as to 

 bear a few flowers on pedicels of their own, while 

 others remain simple. A comjwund panicle is one that 

 branches in this way again and again. 



304. Determinate Inflorescence is that in which tlie 

 flowers are from terminal buds. The simplest case is 

 that of a solitary tei'minal flower, as in Fig. 250. This 

 stops the gro^^•th of the stem; for its terminal bud, 



becoming a blossom, can no more lengthen in the manner of a leaf 

 bud. Any further growth must be from axillary buds developing 

 into branches. If such branches are leafy shoots, at length terminated 

 by single blossoms, the inflorescence still consists of solitary flowers at 

 the summit of stem and branches. But if the flowering branches 

 bear only bracts in place of ordinary leaves, the result is the kind of 

 flower cluster called 



305. A Cyme. — This is commonly a flat-topped or convex flower 

 cluster, like a corymb, except tliat the blossoms are from terminal 

 buds. Figure 2.51 illustrates the simplest cyn)e in a plant with opposite 

 leaves; namely, with three flowers. The middle flower, a, terminates 

 the stem ; tlie two others, bh, terminate branches, one from the axil 

 of each of the uppermost 

 leaves ; and being later than 

 the middle one, the flowering 

 proceeds from the center out- 

 ward, or is centrifugal. This 

 is the opposite of the indeter- 

 minate mode, or tliat where all 

 the flower buds are axillary. 



If flowering branches appear from the axils l)elow, the lower ones are 

 the later, so that the order of blossoming continues cenlrifugnl or, 

 wliich is the same thing, descending, as in Fig. 253, making a sort 

 of reversed raceme or fahe raceme, — a kind of cluster which is to 

 the true raceme iust what the flat cyme is to the corymb, 



