1886-87.] Flotvers of Bolbophyllum Lohbii. 107 



cells correspond to one large cell below, and in this way 

 we get a pit formed with two points directed upwards. The 

 nearer we come to the apex of the labellimi, the deeper are 

 these pits, and in a preparation made by maceration of the 

 epidermis with subsequent staining in andin purple, these pits 

 took up the coloiu', and had very much the appearance of 

 upward-directed hairs, and it was only by making a vertical 

 section through the labellum that I was able to make out the 

 real structure. 



At the yellow spots, already referred to, the cells contain 

 a bright yellow colouring matter in the form of niunerous 

 granules. It is worth noting that the other cells of the 

 labellum also contain this substance, but comparatively only 

 few granules are to be found. Between the three yellow spots 

 there is a tract of small oblong, delicately walled, slightly 

 conjugated cells (fig. 1). The function of these I will after- 

 wards return to. The cells on the under surface of the 

 labellum also protrude, but only slightly, and not so much as 

 those on the upper surface. 



Xow, 1 may state the fimction which those different parts 

 perform in the fertilisation of the flower. Darwin mentions 

 in his work on the Fertilisation of Orchids Bolbophyllum 

 cupreum, B. cocoinum, B. rhizophorce, and B. larUgerum; 

 and he states that in B. rhizophorce two pollen masses are 

 fully exposed, and are attached by viscid matter, and that 

 both are removed at the same time, and that in the same 

 plant the stigmatic chamber, which is very deep, is fitted 

 exactly by one of tlie two pollen masses. He states also that 

 the sides of the oval orifice of the stigmatic chamber slope 

 in after fertilisation, aiid so close the orifice completely, a fact 

 which he did not observe in any other Orchid, and which he 

 presumes is related to the exposed condition of the whole 

 flower. Darwin does not specially mention the labellum, 

 and only conjectures that the extreme flexibility of the label- 

 lum in B. rhizophorce serves to attract the notice of insects. 



When I first saw the flower of B. Lohbii, I came to the 

 conclusion that the labellum had to perform the important 

 function of tilting over and throwing the head or thorax of 

 the insect first against the viscid matter, and then the insect 

 would bring by its withdrawal the head in contact with the 

 pollinia, and so remove at least one of them. To make sure. 



