THE PLANT AND ITS ENEMIES 



1003 



A WELL-PROTECTED CACTUS. 



some instances the hairs all point down- 

 wards, and this is to be observed in the 

 case of certain grasses ; if the thumb and 

 finger are moved up the stem a ver^' per- 

 ceptible roughness may be felt, which is 

 absent when the stem is passed in an 

 opposite direction. In other cases it is 

 not until the visitor actually arrives at 

 the flower that he is confronted with the 

 barrier of hairs. In the case of the 

 common Cornflower the stems and leaves 

 are quite destitute of prickles, but the 

 involucres forming the flower head are 

 bordered with formidable teeth. The lip 

 of the Foxglove is covered with long 

 bristles which guard the entrance to the 

 flower. These do not seem to trouble 

 the humble-bees, which appear to be the 

 only legitimate visitors to the flower. 

 In the case of quite a number of plants, 

 even the filaments of the stamens are 

 clothed with hairs that form barriers in 

 the way of tiny insects which would mount 

 to the pollen-laden anthers. This is seen 

 to a certain extent in the case of the 

 Crocus, and to a much greater degree in 

 the flower of the Bog Asphodel, where the 



stalks of the stamens are quite " furry " 

 in appearance. 



In a certain number of instances the 

 presence of glandular hairs secreting a 

 glutinous substance makes it difficult for 

 creeping insects to get anywhere near to 

 the centre of the flower. This is to be 

 observed in the blossoms of the Goose- 

 berry, and of the LinvcBa. The calyces 

 of the Plumbago and Honeysuckle are so 

 thickly adorned with glandular hairs that 

 small insects not infrequently get stuck 

 fast when tr^ang to approach the flower. 

 This is seen to a much greater extent in 

 the case of the Silcnc nutans, well named 

 the Catchfly. Here the upper part of the 

 stem, as well as the calyx, is viscid, and 

 large numbers of small insects are to be 

 found dead and dying upon the glutinous 

 surface. Just at the time when the 

 Rhododendron flowers are at their best 

 the stem is peculiarly sticky by reason of 

 a mucilaginous substance which is exuded. 

 On this it is possible to find almost any 

 number of little creatures which are 

 captured whilst endeavouring to reach the 

 blossom. S. Leo.nard Bastin. 



