226 THE STRUCTURE OF FLOWERS 



That eminent naturalist, the late Charles Darwin, published in 

 1862 his admirable treatise on the fertilisation of orchids by the 

 aid of insects. Since that time a copious special literature has 

 appeared on the subject. We may mention the names of Herman, 

 Miiller, Delpino, Hugo von Mohl, and Hildebrand, amongst 

 Continental writers ; Charles Uarwin and Sir John Lubbock, 

 amongst our own countrymen ; and Dr. Asa Gray and Dr. Goodale 

 amongst our brethren across the Atlantic. 



Linnaeus and his immediate successors taught that the adjust- 

 ments in hermaphrodite flowers were such on the whole as to 

 secure the application of the pollen of its stamens to the stigma of 

 its pistil or pistils. " The present view," to quote the words of Dr. 

 Asa Gray, " is that this is doubtless strictly secured in certain 

 flowers of a moderate number of species, but never in all the 

 flowers of any such species ; that in ordinary flowers where it may 

 commonly take place, it is not universal ; that in the larger number 

 of species there is something or other in the floral structure which 

 impedes or prevents it." It will be gathered from this definition 

 that some flowers are adapted for close fertilisation, some for cross- 

 fertilisation, some for either. Before proceeding further, let me 

 state for the information of those who have not given much 

 attention to the construction of flowers that they consist of two 

 kinds of organs, viz., what have been apparently called protecting 

 organs or floral envelopes, which when of two sets are named calyx 

 and corolla ; and the essential re])roductive organs which co-oper- 

 ate in the production of seed — the stamens and pistils. 



" A complete flower," to quote from Sir John Lubbock, 

 "consists of (i) an outer envelope or calyx, sometimes tubular, 

 sometimes consisting of separate leaves called sepals ; (2) an inner 

 envelope or corolla which is generally more or less coloured, and 

 which like the calyx is sometimes tubular, sometimes composed 

 of separate leaves called petals ; (3) of one or more stamens, 

 consisting of a stalk or filament and a head or anther, in which the 

 pollen is produced ; and (4) a pistil or an ovary, which is situated 

 in the centre of the flower and contains one or more seeds or 

 ovules. The pistil consists of a stalk or style and a stigma, to 

 which the pollen must find its way in order to fertilise the flower, 

 and which in many familiar instances forms a small head at the top 



