7 



EXPLANATION OF PLATE. 



Fig. l. Portion of stem of Vanilla "plant, with leaf, aerial root, and cluster of flowers ; a, front view of Vanilla 



flower ; fc^side view ; c, aerial root, with root hairs. 



Fig, 2. Single flower of Vanilla, exhibiting the first stage in the process of artificial fertilization. The operator, 



provided with a finely-pointed piece of bamboo, divides the lip or labellum medially, so that the central 

 lobe is separated from tho two side lobes. This exposes the column and organs of fecundation. The in- 

 stalment is represented as placed against tho column, ready to press upwards the anther a, and bring tko 

 pollinia in contact with the stigma b. 



Fig, 3. Single flower of Vanilla, exhibiting the second stage in the process of artificial fertilization ; b shows posi- 

 tion of column exposed by division of the lip [the middle lobe of lip is pulled forward and curled upon 

 itself to show the position of the column ; the side lobes of lip, separated as shown in Fig, 2, are repre- 

 sented at back of the column] ; a, the position of pollen masses, taken from the anther and placed on 

 the stigma. 



Fig. 4. — Enlarged front view of top of the column ; a, the anther. 



Fig. 5. — Enlarged side view of top of the column ; a, the anther ; 6, the stigma, or viscid surface on which the pollen 



masses must be placed to ensure fertilization. 

 Fig. 6. — Enlarged section through top of the column ; a, one of the pollen masses in situ ; b, the stigmatic cavity. 

 Fig. 7.— Enlarged section through top of the column ; a, the pollen masses, having been transferred from a, Fig. 6, 



are now represented in contact with the stigmatic surface. [Although diagramatically shown, these figures 



give a tolerably good idea of what is actually necessary in order to produce fertilization in a VaniHa 



flower.] 



The cultivation of Vanilla has been attempted in numerous tropical Colonies, but, with the sole exception 

 of Mauritius and tho Seychelles, it does not appear to have assumed an important position in any British 

 Colony. This is due to a variety of circumstances. In some Colonies tho climate may be unsuited to the suc- 

 cessful growth of the plant, owing to seasons of extreme severity in droughts or heavy rains. In others, the 

 Boil may be too retentive. In most of them, the need which exists for artificially fertilizing the flowers of 

 Vanilla, and the care necesssary to properly cure the pods have, no doubt, contributed to retard the cultivation. 

 There are, however, no valid reasons why the cultivation of Vanilla in certain portions, at least, of the West 

 Indian Colonies, of British Honduras, of the West African Settlements, of India, Ceylon, and the Straits Settle- 

 ments should not be successfully pursued. With that view plants of Vanilla have been forwarded from Kew 

 to certain Colonies where they did not previously exist, and it is proposed now to give very briefly the chief 

 points bearing upon the industry. 



The A anilla plant is an orchid of climbing habit, of which there are probably several species under culti- 

 vation. The more common plant appears to be Vanilla planifolia, Amir. (V. claviculata, S\v.) Other spe- 

 cies under cultivation are V. aromatica, Sw. and V. grandiflora, Eich. The botany of the plants yielding 

 Vanilla requires to be carefully investigated. The specimens in the herbarium of this establishment in their 

 present state throw little light on the subject. Hence a good series of leaves, flowers and fruits of plants 

 yielding Vanilla, carefully dried, or preserved in spirit, would be a valuable addition to the collections. 



It appears that Seleaipedium Chica, Bchb. f. (Xenia Orchidacea, Vol. L, p. 3, t. 2) yields Vanilla on the 

 Isthmus of Panama, which is described by Seeman (Botany of Herald, p 2J5) as follows : — 



"The fruit of this plant is highly esteemed as an aromatic by the inhabitants of the Isthmus [Panama}, 

 "and used for all purposes for which real Vanilla is commonly used It is termed 'Vanilla Chica,' or ' Little 

 " Vanilla,' because its fruit is very much smaller than that of any of the genus Vanilla found in the Isthmus." 



Cultivation. — As regards starting a Vanilla plantation, it is important to bear in mind that the plantg 

 being climbers, it is necessary to provide them with support of some kind, and generally, for this purpose, 

 rough-barked trees, trellis-work, stone pillars, or stone walls are utilized. Living stems of rough-bark trees 

 are probably the best support for Vanilla. In Mauritius, the Seychelles, and Reunion, the stems of Jatropha 

 Curcas are largely used. In addition to support, the Vanilla plants require a certain amount of shade. This 

 however, should not exceed what is called half-shade (demi jour) . A certain amount of sun is, however, essen- 

 tial to the proper ripening of the pods. Whatever the support or nature of the shade may be, it is important 

 to bear in mind that the Vanilla plants should be kept within easy reach of the cultivator, and not allowed to 

 climb high up amongst the branches. 



The ground around the support should be prepared by deep trenching to the depth of a foot or 18 inches. 



The drainage of the bed should be perfect. The most favourable soil consists of fine rich loam, mixed 

 with equal parts of sand and leaf mould. Rich animal manure, or manure of any kind, is not a desirable ad- 

 dition. To renovate the soil at the end of the season, add some well-rotted vegetable mould or humus mixed 

 with sand. Baise the bed about six inches above the surrounding surface, and support by means of stones 

 or rockwork. Where obtainable, the cutting should consist cf portions of stems about two or three feet long, 

 but all the better if four or five feet long. The leaves are first removed from the lower part, and three joints 

 are laid under the soil and covered to a depth of two or three inches. The upper part of the stem is trained 

 against the support in the position in which it is intended to grow. A single tree will carry several Vanilla 

 plants, depending upon its size. The surface of the bed should be kept moist by being covered with leaves 

 or "mulching" and, in very dry weather, it should be regularly watered. 



Thus started, Vanilla cuttings readily take root, and the stem will grow and flourish. Depending upon 

 the size of the cuttings, the plants begin to flower in the second year after planting. They do not, however, 

 flower freely until the third and fourth years. 



Fertilization of the floicers. — The first duty of the cultivator when the plants are in flower is to attend to 

 the duty of fertilization which, in countries where the Vanilla is not a native, will require to be done arti- 

 ficially. The flower of the Vanilla, as in most orchids, is a very highly differentiated organ, the parts of 

 which can be best studied by a reference to the engraving given on page 6. In the wild state, the pollen 

 is carried to the stigma of the Vanilla flower by means of the agency of insects. Where these particular in- 

 sects are absent, their work must be performed by the cultivator, or no Vanilla pods will be produced. 



It is recommended that the work of fertilization should take place in the morning. It is advisable that 

 all the flowers in a cluster be fertilized as they open ; but of those that are successfully fertilized, only a cer- 

 tain number, depending on the age and strength of the vine, should be allowed to remain. If too many pods 

 are retained at first, the vine is apt to be weakened, and the quality of the produce lowered. 



