192 OUR INSECT FRIENDS AND FOES 



anther, which is confluent with the style and 

 forms the so-called "column." This anther is 

 divided into two cells, which are frequently so 

 developed as to have the appearance of two 

 separate anthers. In most Orchids the pollen 

 coheres in masses supported on a stalk or 

 " caudicle," forming together the " pollinia." 

 Theoretically there are three styles, but the 

 stigma of the upper one is modified into a re- 

 markable organ called the "rostellum" (at the 

 base of the caudicle), while the two lower ones are 

 frequently so closely united as to appear like 

 one. If we look at a flower of the common 

 Orchis mascula, or O. Mono of our meadows, we 

 shall see that the lip-petal or labellum upon 

 which the visiting insects alight, is continued as 

 a spur or tube, the so-called nectary. The stigma 

 is bilobed, and consists of two almost confluent 

 stigmas, lying directly under the pouch-formed 

 rostellum. The anther consists of two fairly 

 widely separated cells, which are longitudinally 

 open in front, each cell including a pollen-mass or 

 pollinium. A pollinium, if closely examined, 

 will be seen to be composed of a number of 

 wedge-shaped packets of pollen grains, united 

 together by extremely elastic, thin threads. At 

 the lower end of each pollen-mass the threads 

 become confluent and compose the straight 

 elastic stalk or caudicle. The end of the caudicle 

 is in turn firmly attached to a viscid disc, con- 

 sisting of a minute oval piece of membrane which 

 has a ball of viscid matter on its underside. 

 Each pollinium has its separate disc, the two 

 balls of sticky matter lying close together within 



