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A TEXTBOOK OF THEORETICAL BOTANY 



We may instance one case which was studied by Miiller, as an example. 

 The flowers of Herminium monorchis are very small and greenish-white in 

 colour, and emit an odour of honey (Figs. 1258 and 1259). 



The three petals are much alike and 

 form a tube, the labellum not being 

 specially modified. There are two 

 lateral stigmatic surfaces and above each 

 is a disc, to the back of which are 

 attached the caudicles of the pollinia 

 belonging to the two fertile anthers. 

 The discs are hard, but each has a 

 hollow base which is viscid and into 

 which any thin object slips. The insect 

 visitors are small Hymenoptera, Dip- 

 tera and Coleoptera, about i mm. long. 

 The insect enters from the corner be- 

 tween the labellum and one of the up- 

 right petals. It can only get in its 

 head and forelimbs and it is the latter 

 which make contact with the discs 

 and so become attached to the pollinia, 

 which, if strong enough, the insect 

 pulls out. This is followed, as usual, 

 by the contraction of the caudicles and 

 the pollinia are then ready to strike the 

 stigmas of another flower. 



We have described a few of the 

 almost infinitely varied means whereby 

 pollination of flowers is ensured and 

 cross-pollination favoured. A com- 

 paratively late comer in the field of 

 Botany and strangely neglected. Floral 

 Biology oflFers rich prizes of interest to those who have patience to study it 

 for themselves. Darwin expressed his conviction that there was scarcely 

 a single point of floral construction, however seemingly trivial, which did 

 not have a meaning and a function that devoted study would reveal. How- 

 ever incomplete our knowledge of floral mechanism may be, records of the 

 insect visitors are yet more imperfect. In many cases, even among common 

 flowers, the identity of the pollinator rests upon a few isolated records, 

 while in too many other cases it rests more on deductions from the shape 

 of the flower than upon observations of the insects themselves in the act of 

 pollination. When we contemplate the legions of the world's flowers it is 

 easily grasped how very, very little we know about the inner life of even the 

 more familiar among them. In the complex and beautiful interplay of 

 structure and function at this critical point in the plant's life history, lie more 

 problems of morphogenesis and organismal control than we can well imagine. 



Fig. 1259. — HerniiniKiii monorchis. 

 Habit photograph. Box Hill, Surrey. 



