180 



BRITISH PLANTS 



the flowers, which are small, are clustered into head-like 

 racemes. 



The spike (Fig. 77) and its variety, the catkin, are repre- 

 sented chiefly by wind-pollinated plants — e.g., plantain, 

 hazel, alder, birch. Some grasses possess compound spikes. 

 The orchids have stalkless flowers on an elongated axis, 

 and, morphologically, these inflorescences are spikes ; 

 but the usually long inferior ovary behaves as a stalk. 



^ 



il 



^ 

 ^ 

 ^ 



^ 



2 





Fio. 77. — ^Diagram of 

 Sfiee. 



Fio. 78. — ^Wiixow-hbrb : LoNGiruriNAL 

 Sectiok of Floweb showing Long, 

 Stalk-like IsrEKiOR Ovary (a). 



Btyle ; e, stigmas ; d, stamens ; 

 e, petals ; /, sepals. 



6. 



80 that the flowers stand away from the axis, and 

 biologically the inflorescence is a raceme. The same 

 is true of the evening-primrose and some wUlowherbs 

 (Fig. 78). 



The cyme (Fig. 79) is found in the Pink family and the 

 valerians. The main axis ends in a flower, and one or 

 two branches arise immediately below, which in their 

 turn end in flowers. This method of branching continues 

 until a large usually flat-topped inflorescence is produced. 



