432 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XVI. 



as sepals. The two interior and lateral, similar to these, are the petals, 

 and the lowermost of this series, which is usually very distinct in shape, 

 is called the labellum or lip. This often has a sac-like cavitv projecting 

 downwards from its base called the spur, and its surface usually presents 

 three distinct parts, two projections of varying shapes on the sides called 

 the lateral lobes and the terminal or mid-lobe. The centre of the lip 

 is often furnished with longitudinal groves or ridges. 



The column stands in the centre of the flower. This is usually semi- 

 cylindrical and curved and flattened on the side facing the lip. At 

 the top of the column is the anther, the loose lid-like part is the oper 

 culum, and the top of the column itself is sometimes produced into a 

 beak or rostellum.. 



If the operculum be lifted off carefully with a pin, the pollinia or 

 masses of pollen grains may be seen lying within the shallow anther- 

 cells. These pollen grains may cohere into 1, 2 or •! pairs of oblong, 

 globose or pear-shaped waxy or glandular masses, which are free from 

 each other or are attached by pairs or fours to a gland or a stalk 

 (caudicle) may intervene between the pollen masses and gland. (In a 

 Dendrobium, for example, the pollen masses cohere in pairs, each pair 

 in its own anther cell, but they are otherwise quite free, so that, on 

 lifting and removing the operculum, if care be not taken, the pollen 

 masses fall out ; in iErides, on the contrary, on lifting the operculum, 

 the gland will immediately attach itself to the pencil, pin, or whatever 

 instrument is used.) 



In front of and just beneath the anther is a viscid cavity called the 

 stigma. Fertilisation of the ovules in the ovary is effected by tubes 

 issuing from the pollen passing through the body of the column length- 

 wise by way of the stigma and thus reaching the ovules. 



CLASSIFICATION. 



The first division of Bombay Orchids is into Tribes, of which there 

 are four. (As this primary classification is based on characters derived 

 from the pollinia it is necessary to use a hand lens to distinguish thcra 

 correctly.) The following are their chief characters : — 



Tribe I. Ejjidendrece. 



Anther cells parallel distinct. Pollinia waxy, 1 to 4 in each cell, 

 free, or those of each cell cohering at the base by a viscid 

 appendage. 



