230 



THE AGRICULTURAL NEWS. 



July 2'i 



1918. 



WATER-LILIES IN ST. VINCENT. 



The loUowing interesting notes on the abo\e sub- 

 ject are contributed by Mr. W. N. Sands, the Agricul- 

 tural Superintendeno in .St. Vincent: — 



All the streams in 8t. Vincent are swift, running from 

 mountain to sea, and the coastal lands are well raised above 

 sea level, consequently there are no swamps. < )wing also to 

 the light volcanic soil, ponds retain water for short periods 

 only, with the result that there are few striking flowering 

 water plants. Attempt.s to introduce these plants into pools 

 in rivers have not been .successful, because the pools 

 are so frequentl}- washed out during heavy rains. As far as 

 the writer is aware, the water-lily (Nvmpiiafa ampla) is 

 found only in one small pond in the colony, and this dries 

 up after the rainy season every year. Sporadic efforts have 

 been made from time to time to grow aquatic plants in gar- 

 dens, but these have not been viewed with favour by the 

 .sanitary authorities, owing to the fact that the tanks or tubs 

 often served as breeding places for mosquitoes. This disability, 

 however, can be easily remedied now that a permanent 

 source of supply of the 'millions' fish (Girardiiiiis pocci/oidcx) 

 is maintained in the Botanic Gardens. 



In the year 191-^ a large circular concrete basin or pond, 

 30 feet in diameter and 2 feet deep, was constructed in the 

 gardens, in order that water plants, more particularly the 

 true water-lilies of the genera Nyraphaea and Victoria, 

 might be cultivated. With t! e idea that a s liort account of 

 the experience gained in the growth of certain of these might 

 be of interest to others in the West Indies, these notes have 

 been written. 



The water-lilies, with the exception of the \'iit<)ria 

 regia, are grown in tubs 14 inches high. Cement barrels 

 .sawn in half have been found suitable for the purpose, as 

 they do not readily rot under water. Jlven strong-growing 

 nymphaeas will thrive and flower freely in these tubs without 

 it being found necessary to transplant them. Other advan- 

 tages are: (a) the water of the pond can be kept fresh and 

 clear, and free of decaying vegetable matter, and (b) the 

 growth of individual plants can be controlled. 



In preparing tubs for planting, holes are bored with 

 a large auger in the bottom of each, as well as around the 

 sides, about 3 inches from the base. To insure proper 

 drainage, a layer of stones or broken crocks is placed 

 inside the tubs, covering the holes, and on this is placed 

 a layer of rotten wood. The soil mixture or compost u.sed 

 consists of good loam,' cotton-seed meal, and wood-ashes, 

 in the proportion of 10: 2: \ by volume. This lias given 

 excellent results, and it has not been uncommon for a single 

 plant to produce eight or nine flowers at one time, some of 

 which have exceeded 12 inches in diameter, liefore the 

 cotton-seed meal and wood-ashes were used, green filaiuen- 

 lous algae, known as 'moss', produced very unsi^ihtly effects 

 in the pond each spring, (,'opper sulphate might perhaps 

 have been used to control the algae, but for various reasons 

 it was considered inadvisable to use it. Whether it was 

 a mere coincidence or not has not been ascertained, stHI 

 the fact remains that after using the above mixture the 

 algae disappeared completely, and gave no further trouble. 

 It may be added that other rich soil composts could be used 

 for the tubs, or varied to suit {larticular circumstances. 



When planting the different kinds of nymphaeas, small 

 plants are selected from those which have grown up aroun<l 



the old flowering heads. Suckers were usually produced in 

 considerable numbers in the X. I.otia: and X. tulxrosa hybrids 

 and varieties that have been grown. One young plant of 

 strong-growing kindc, and two or three of those less robust, 

 ate set in each tub just before it is submerged. Small tubers 

 may also be used, especially of tho.se varieties that have 

 a distinct resting period each year even in presence of an 

 abundant supply of water and a slight fall of a few degrees 

 only in temperature. 



For the Victoria regia, a bed is formed in the centre of 

 the basin with the same soil mixture as described above. 

 The soil is kept in position by means of a circle of large 

 stones built up to the requisite height of 14 inches: this, as 

 in the case of the nymphaeas, allows of a maximum depth 

 of water of 10 inches covering the soil, which is ample. 

 Seedlings of the lilies are raised annually from seed produced 

 in the pond, and one of these is planted in the bed. 



The plants must be fully exposed to sunlight, and shel- 

 tered from high winds. They require little attention subse- 

 quently, but it is necessary every week to take off exhausted 

 or damaged leaves and flowers, in order to keep them in good 

 healthy condition. 



Tiie raising of new kinds ot water-lilies is (|uite easy, and 

 repays attention. Our experience has hitherto been confined 

 to the raising of hybrids between ^\'. Lotus and .^'. tni'irosu, 

 and we have already obtained some beautiful forms. These 

 two species were selected, because (I) the diurnal movements 

 of the floral organs were practically identical, and gave most 

 promise of early success, and (2) because only a small number 

 of seedlings could be tested at one time. It may be explained 

 that certain groups of nymphaeas flower by night, and others 

 in the day. For example, tbe flowers of X. Lotus and X. tiihr- 

 iiS'.i begin to open after dark, remain fully open all through 

 the night, and commence to close soon after sunrise. They 

 are quite closed by 10 a.m. Kgitxa X. zanziliaroisis starts 

 to open about 930 a.m., remains fully open al! day, and 

 closes about 6 p.m. A variety of this species, X. 'Aimihur- 

 t/tsis, var. rosra, commences to o|)en soon after sunrise, and 

 closes about 5 p.m. Apart from the question of raising • 

 seedlings, it is important to note that unless the pond 

 is visited before 10 a.m., or by moonlight, ^V. /.ot//s and 

 .V. tiilnrostj are not seen with open flowers, whereas the full 

 beauty of X. zaiizilmrensis cannot be .seen until after 10 a.m. 



The flowers are frequented .soon after sunrise by the 

 honey-bee (.-///.v )ncllifern). This is the chief insect visitor 

 observed. Night flying insects have not yet been seen on 

 the flowers. The honeybee does not confine itself to visiting 

 flowers of one eolotir only, but has often been noticed to col- 

 lect pollen from white, pink, and red flowers in succession. It 

 is this fact which renders common the production of natural 

 hybrids. 



( )wing to the limited facilities for handling seedlings, 

 the i)ractice is to allow only one or two flowers on selected 

 plants to mature .seed All the other flowers, as soon as they 

 have faded, are taken ofl'. It is often diflicult to ascertain 

 when the fruit is ripe, for after flowering the flower-stalk 

 bends outwards and downwards, and submerges the fruit, 

 which ripens under water, or rather, gradually decays. When 

 sulliciently dei;ayed, the .seeds are liberated. To each seed is 

 attached a spongy mass of tissue filled with air, by means of 

 which the .seeds are enabled to float, and are dispersed over 

 the surface of the water. After a few hours the tissue loses 

 the air, and the seed sinks. Some days later, provided the 

 i-onditions are suitable, the seed germinates. The Tirtorin 

 rtxi<' bed in the centre of the pond provides a suitable nidus, 

 and it is usually possible to obtain an adeijuatc number of 

 seedlings from this source for testing purpo.ses. At a' very 



