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, 



M 

 I 

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2 

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F IG . 77. DIAGRAM OF FIG. 78. WILLOW-HERB : LONGITUDINAL 



SPIKE. SECTION OF" FLOWER SHOWING LONG, 



STALK-LIKE INFERIOR OVARY (a). 



b, style ; c, stigmas ; d, stamens ; 

 e, petals;/, sepals. 



so 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 Willowherbs 

 (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. 



