SOME PLANT MARRIAGES 



433 



flowers becomes their ruin. Thrusting their probosces in the slits to get at 

 the nectar, they are held fast, and all their struggles to liberate themselves 

 only fix them tighter. With their heads 

 in the tubes of the corollas, and their 

 bodies and wings projecting, they die a 

 lingering death. 



We come now to the Orchids. The 

 parts of an Orchid flower have been 

 described in the previous chapter, 

 where also the pollination of a British 

 orchid, the Common Twayblade (Listera 

 ovata), is briefly described. Perhaps it 

 will not be taken amiss if, before going 

 farther afield, we direct attention to 

 another British species the Spotted 

 Orchis (Orchis maculata) the pollina- 

 tion of which differs from that of the 

 Twayblade in some important parti- 

 culars. 



It will be seen (fig. 533) that the 

 sepals and two upper petals of this 

 flower arch over the pollinia and rostel- 

 lum, and that the inferior petal or lip 

 affords an excellent landing-stage for 

 visitors. This petal is prolonged back- 

 wards into a hollow spur, which takes 

 the place of a nectary ; for though it 

 secretes no free honey, its delicate and 

 succulent tissue is much prized by flies 

 and bees. The pouched rostellum, 

 which contains a brownish and viscid 

 matter, projects into the mouth of the 

 spur and also overhangs the two stig- 

 matic surfaces ; while the only perfect 

 anther (the others are mere rudiments) 

 stands immediately above it. Now, an 

 insect visiting the flower and dipping 

 its head into the spur, necessarily 

 strikes against the rostellum. In so 

 doing the pouch gets ruptured, and 

 as the ruptured membrane curls back, 

 it brings into view two viscid discs or 

 balls in close connection with the caudi- 

 cles (stalks) of the pollinia. These 

 n10 



Photo by] [E. Step. 



FIG. 536. GREEN-MAN ORCHIS (Aceras 



anthropophora ) . 



The divisions of the long lip are supposed to represent 



the human figure, the arched sepals forming the head. 



The arrangements are much like those of the Purple 



Orchis. 



