ORCHIDS OF JAMAICA 



upper face of the rostellum (as in Maxillaria). In some cases 

 short true caudicles are formed, by which the pollinia are 

 attached to the pedicels. 



The ovary is generally somewhat cylindrical-ellipsoidal or 

 spindle-shajied, and often bears longitudinal lines, ridges, or 

 wings, which become further developed in the fruit. 



The fruit is a dry capsule, except in Vanilla, crowned by the 

 withered remains of the flower, and opening usually by six longi- 

 tudinal slits, forming three broad and three narrow valves, which 

 remain united above and below ; in Harrisella they are free above. 

 In Pleurothallis there are only two slits. In Vanilla the fruit is 

 fleshy and pod-like. The seeds are innumerable and minute, 

 and contain a small rudimentary few-celled embryo enveloped 

 by a thin loose membranous coat, which varies much in shape 

 and colour. They are scattered by aid of hygroscopic hairs on 

 the interior of the valves, and are carried by the wind. 



The family falls into two groups, a small one, Diandrse, not 

 represented in Jamaica, with two or rarely three fertile stamens, 

 and a large one, Monandrse, with one fertile stamen. 



The subdivision of the Monandrse was based by John Lindley 

 (The Genera and Species of Orchidaceous Plants, 1840) solely on 

 characters derived from the anther, the pollen, or the pollen- 

 distributing apparatus. Lindley recognised six tribes. E. Pfitzer, 

 who more recently elaborated the family in Engler and Prantl's 

 Pflanzenfarnilien (ii. part 6, 1889), criticises this arrangement, 

 which was practically followed by Bentham and Hooker in the 

 Genera Plantarum (iii. 1883), as depending too much on the 

 relation of the floral structure to insect visits for the purpose of 

 pollination, and too little on a general study of the whole plant. 

 He retains the Oplirydese which are characterised by the per- 

 sistent terminal erect anther (to which belongs Habenaria), but 

 subdivides the remainder into twenty-eight tribes, based on the 

 terminal or lateral character of the inflorescence, the develop- 

 ment of the leaf and stem, and the form and relative size of 

 the lip. We have followed the sequence of genera in Pfitzer's 

 arrangement. 



