JIOBPHOLOGY OP BEPEODUCTIVE OEGANS 111 



peduncle, are of different lengths (fig. 210), those (a", a'') at the 

 base of the primary axis a' longer than those towards and 

 at the apex, so that the whole form a level, or nearly level, top. 

 Examples may be seen in some species of Prumis (fig. '210) . 

 It frequently happens that after flowering the primary axis 

 elongates, and the corymb becomes a raceme ; this may be 

 seen in many cruciferous plants, such as the Wall-flower or 

 Stock. 



c. The Anthela. — In several species of Juncus and Luzula 

 the pedicels of the lower flowers are so long that they are 

 elevated above the upper ones. The form of the inflorescence 

 so becomes concave on the upper surface. This variety is 

 known as the anthela. 



Fig. 211. 



Fi'j. 210, Simple corymb of a species of Prunus {Cerasns). a'. Primary 

 axis, bearing bracts, 6, h^ from the axis of wliiGli pedicels, a'\ a", arise. 

 /'(■(/■ -il. Compound or brancJnng corymb of the Wild Service tree 

 ( I'iinis torminaiis). a'. Primary axis, a", a". Secondary axes, a'", a'". 

 Tertiary axes, b, h, h. Bracts. 



d. The Spike. — This differs from the raceme only in the 

 flowers being sessile on the main peduncle ; or if there are 

 any pedicels, they are so short as to be indistinguishable 

 without removing the flowers from the axis. Examples of 

 it may be seen in the Eib-grass (fig. 212) or the Vervain 

 (^1,7.213). 



There are four kinds of indefinite inflorescence which 



