

THE FLOWER SHOOT 149 



the flowers on lateral axes are solitary in the axils of the bracts. 

 The choke cherry, currant, pokeweed, sourwood, etc., are 

 examples of a raceme (fig. 106). Compound racemes are formed 

 when by branching of the flower shoot there are several racemes 

 in a cluster, as in the false Solmon's seal (Smilacina racemosa). 

 2. The panicle. The panicle is developed from the raceme 

 type by the branching of the lateral flower-axes forming a loose 

 open flower cluster, as in the oat (fig. 399). 



Fig. 1 06. Fig. 107. 



Choke-cherry (Primus virginiana). An umbel (milkweed, Asdepias cornuti, 



Leaves, flower-raceme, and section of reduced one-half length), 

 flower at right. 



3. The thyrsus is a compact panicle of pyramidal form, as in 

 the lilac, horse chestnut, etc. 



4. The corymb. The corymb shows likewise an easy transi- 

 tion from the raceme type, by the shortening of the main axis of 

 inflorescence, and the lengthening of the lower, lateral flower 

 peduncles so that the flower cluster is more or less flattened on 

 top. This represents the simple corymb. A compound corymb 

 is one in which some of the flower peduncles branch again form- 



