12 



i;knk!;at, i;i;vii:\v <\v 'hik (tKCHiDKF. 



Graininancris Ellisii. 



Tint notwithstanding tliis apparently endless and irreconcileable 

 variety in form, a general plan of floral structure pervades the 

 whole family of orchids that clearly distinguishes it from every 

 other Natural Order of plants. The floral organs like those of all 

 endogenous plants are constructed upon a trimerous (tripartite) type, 

 that is to say — all the parts are in threes or a simple multiple of 

 three; * but owing to the suppression of some, the confluence of 

 others, and vai-ious other modifications especially of the sexual organs, 

 the tripartite typo, except in the two series of perianth segments, 

 is greatly disguised, but as will be presently pointed out it is 

 almost always present. Irregular as the flowers appear on superficial 

 view, there may always be detected in them a bilateral symmetry, 

 that is to say — all normally developed orchid flowers may, in one 

 direction only, be divided in a monosymmetrical manner or into two 

 equal parts that resemble each other in every particular.t Into 

 whatever form, amidst the almost infinite variety of changes that 

 runs through the whole family, an orchid flower has been moulded, 

 and whatever modification an individual organ may have undergone, 

 the following characters are presented to the naked eye throughout 

 and may be generally recoguised without difficulty. 



* The anthers only of the theoretical type of orchid flowers are a multiple of three (3 x 2), 

 but the rudiments of all the six are generally proseut, as will be shown further on, 



t Z\'gomorphy of the Ocrnian botanists. 



