38 



shoot branches two main types of inflorescence are distin- 

 guished as under, although here, as in other cases, intermedi- 

 ate forms are found : 



(1) Monopodial or racemose. Here there is a distinct main 



axis formed by the continued elongation of the 

 parent flowering shoot. 



(2) Cymose. Here there is no main axis formed by the 



elongation of the parent flowering shoot and lateral 

 flowering shoots grow more vigorously than the 



o <-> c? */ 



parent axis. 

 The principal kinds of racemose inflorescences are : 



(a) Raceme. The main axis is elongated and bears 

 pedicellate flowers. 



(6) Corymb. This ia a raceme in which the main axis 

 is short and the lower pedicels are longer than 

 the upper ones, the inflorescence being more or 

 less flattened and with a convex outline. 



If in a raceme, or corymb, the main axis, instead of directly 

 producing pedicels, develops lateral branches which, directly 

 or indirectly, bear the pedicels, we get a compound-raceme or 

 -corymb, respectively. 



(c) Spike. The main axis is elongated and bears sessile 



flowers. A small spike is called a spikelet. A 

 spike having inconspicuous unisexual flowers 

 and which falls off entire from the plant after 

 flowering, or fruiting, is a catkin. It is usually 

 pendulous. 



(d) Spadix is a spike with a thick or fleshy axis. A 



spadix is usually more or less enclosed in a large 

 bract which is called the spathe. In palms the 

 spadix is branched and has several spathes. 



(e) Umbel. The main axis bears a number of pedicel- 



late flowers at its apex. The pedicels which all 

 radiate from the same point are called the rays 

 of the umbel. At the apex of the peduncle 

 bracts are often found forming a whorl below the 

 pedicels, or rays, which is called the involucre. 

 When the rays instead of bearing flowers bear 

 secondary umbels, the latter are termed umbellules 

 and their involucres are involucels, while the 

 inflorescence becomes a compound umbel. 

 (/) Head or Capitulum. The main axis bears a number 

 of sessile flowers at its apex. Here also there 



