COLENSO. — On Four Notable Foreign Plants. 3il 



under cultivation, and a crop which seldom falls below 

 200,0001b., while the quality has been so greatly improved by 

 careful cultivation and preparation that Mexico is beginning to 

 feel uneasy. What is known in commerce as " inferior Bour- 

 bon " is actually the product of our colonies of Mauritius 

 ■and the Seychelles. Brazil, Peru, and other parts of South 

 America are also in the market with their vanillas, while the 

 Pacific coast is well supplied from Tahiti and the Sandwich 

 Islands ; and, as the market does not appear to be glutted— 

 the perfumer and the confectioner finding a use for all that is 

 raised — it is likely that West Africa and all the West Indies 

 will before long enter the field ; for, notwithstanding that the 

 planifolia of Mexico is still the best of the vanilla species, it is 

 quite capable of being transplanted, and it is notorious that 

 several of the other varieties are wonderfully improved by 

 being grown a little less at haphazard than in their native 

 woods. But every sky will not suit the vanilla orchid. The 

 soil is of slight moment, since the plant, clinging for support to 

 trees or to trellis-work, derives a large portion of its nourish- 

 ment from aerial roots, as is the case with some of our in- 

 digenous epiphytal orchids, only these do not arise from the 

 ground. The climate seems to be all-important, for the plant 

 requires a mean temperature of between 75° and 80'^, and a 

 damp, steaming atmosphere. Its long, fleshy pods take some 

 six months, or more, to arrive at perfection, and constitute the 

 portion of the plant in which lie its peculiar virtues. A clear- 

 ing is made in some damp part of the forest, a few trees being 

 left to serve as supports for the vanilla-plants, which are 

 then planted out in the shape of cuttings, and left to the 

 kindly action of the equatorial sun. In three years they are 

 ready for harvesting, and for thirty more will yield pods 

 •enough to pay for the gathering. Nor is much care required, 

 except to aid the fertilisation of the flowers by artificial means. 

 But in Mexico this is not needed, and the process of fertilisa- 

 tion (which in no orchid, as Darwin has taught us, can be 

 efl'ected by itself) is accomplished by means of native insects. 

 Yet it is known from experience that even artificial fertilisa- 

 rtion has to be performed with judicious care ; for, were all the 

 flowers to be fertilised, the result would be an overflowing 

 crop one season, but almost certain death to the plants 

 through exhaustion before another season arrived. Then 

 comes the plucking, each pod being detached as it ripens, a 

 crackling sound as it is passed between the fingers being the 

 criterion as to its ripeness. After being dried in the sun the 

 pods are slightly fermented, to develope their peculiar odour, 

 .-and, in some places, — for the modus operandi differs in different 

 countries, — rubbed over with oil before they ai-e sent to market. 

 .Long experience is required, not so much for the cultivation of 



