THE ANGIOSPERMAE 



1285 



I. Catkin Type 



This type of pollination is often referred to as the amentiferous type 

 because the great majority of the species which exhibit it belong to the 

 Benthamian group of the Amentiferae. In these species the male inflores- 

 cence is a catkin, that is a long inflorescence made up of male flowers which 

 are individually immobile, but are collectively attached to an elongated axis 

 which can be readily shaken by the wind. The female catkins are shorter 

 and relatively immobile, but with large stigmas (see Fig. 1189, p. 1230). 

 Good examples are seen in such common catkin-bearing trees as Coryhis 

 avellana (Hazel) and Betiila verrucosa (Birch). Although the catkins of 

 Salix (Willow) are usually bee-pollinated there are a few species in which 

 the nectaries have become petaloid and they are therefore wind-pollinated. 



As a standard example of this type we may instance the Oak, Oiiercus 

 (Fig. 1 2 17). The trees are monoecious, the staminate and carpellary flowers 



B 



Fig. 1217. — Quercus petraea. A, Flowering shoot; male catkins on left, 

 sessile female flowers on right. B, Young male flowers. C, Female 

 flower. D, Older male flower. E, Female flower in vertical section 

 (B, C and E after Le Maout and Decaisne.) 



