2io8 



A TEXTBOOK OF THEORETICAL BOTANY 



the column so that the polHnia carried by an insect may be brought into 

 contact with the stigma. 



Our final example of this group is the curious genus Neottia. There are 

 only three species in Europe and Asia but one, A^. nidus-avis (Fig. 2047) 

 (Bird's-nest Orchid), occurs in Britain. It is a leafless saprophyte whose 



Fig. 2047. — Neottia mdus-avis. Inflorescence, in a 

 Surrey wood. 



rhizome gives off a large number of branches and roots which become 

 grouped together to form a solid mass resembling an underground bird's 

 nest. It lives by means of a mycorrhizal fungus, upon the humus in the 

 woods, especially in beech woods. Although originally the adventitious 

 roots possess a typical root apex with a root cap, it is stated that at times 

 they may lose the cap and function as stems, producing aerial shoots. The 

 flower (Fig. 2048) spikes are long and the flowers are brownish-yellow in 

 colour. The pollination mechanism is similar to that in Listera but the 

 nectar is concealed in the labellum, which forms a shallow bowl, and it is 

 therefore not so exposed as in the Tway-blade. Furthermore the pollinia 

 adhere less firmly. If insects fail to visit the inconspicuous flowers self- 



