538 MR. II. O. FORBES ON 



On the Contrivances for ensuring Self-fertilkation m some Tro- 

 pical Orchids. By Henry O. Tories, F.R.G.S., F.Z.S. 

 (Communicated by H. N. Eidlet, F.L.S.) 



[Read 18th December, 1884.] 



(Plates XVI. & XVII.) 



During my recent sojourn in the Dutch East Indies, I resided 

 for a considerable period on the estate of Kosala in the West 

 Javan hills, where I had excellent opportunities for making 

 many observations on the fertilization of the Orchids growing in 

 the forest in the immediate neighbourhood of the house, or in 

 the garden attached thereto, whither I transplanted many species. 

 Of these observations I desire to lay before the Society the 

 following short account : — 



Cymbidium stapelioides, Teijsm. et Binn. — I found this rather 

 rare Orchid in flower at a height of 2600 feet above the sea. I 

 transplanted it to a tree 1000 feet lower down. None of the 

 flowers, which were expanded when I found it, were fertilized, but 

 one of the stems had a solitary capsule. For three weeks the 

 plant remained in the condition in which it was found, its large 

 and somewhat sombre flowers retaining their perfect freshness 

 throughout. I then took compassion on its barren state, and ferti- 

 lized four of its flowers with pollen from others on the neigh- 

 bouring stems. These alone bore any fruit. A couple of months 

 later a fine new spike appeared, which I left to its own resources, 

 for between four and five weeks it exhibited a very fine compact 

 truss of twelve flowers ; but not one seed-capsule was produced. 

 Insect life at the lower station seemed quite as abundant as 

 at the higher. This Orchid possesses no nectary, and its odour, 

 if not pleasant, is not disagreeable. The viscid disk of the 

 pollinia is remarkable for its elasticity ; after removing on my 

 pencil-point the pollinia from the anther and applying them to a 

 stigma, the adhesion between stigma and pollen was not so great 

 as between the pencil and the pollen, the viscid disk stretching 

 quite one eighth of an inch, but yet withdrawing wholly the 

 pollinia from the stigma, without leaving any grains on the 

 Rtigma. Even after the pollinia had been a week removed from 

 the flower, the elasticity of the disk was unimpaired. 



One of the prettiest and commonest Orchids of the neighbour- 

 hood was the pure white Dendrobiwn cruvienafvm, Swarts., of 



