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Disa (Derivation unknown probably)

(derivation unknown; probably a native name). ORD. Orchideae. A genus of about fifty species of terrestrial Orchids, natives of tropical and South Africa, and the Mascarene Islands. All are very pretty and interesting, but the number worth cultivating is somewhat limited. Of these, the best is D. grandiflora, sometimes known as the Flower of the Gods. Its culture, though considered by many to be difficult, is comparatively easy, where proper means and site are employed. With regard to its native surroundings, it should be borne in mind that the streams, &c., upon or near the margins of which it grows, are water gorges during some portion of the winter months, and occasionally very dry in the summer. The plants should be kept quite cool in winter, but not allowed to become too dry at any time. By the end of February, more water should be given; and from April until the flower-spikes are formed, too great a quantity cannot well be applied. D. grandiflora is one of the most beautiful of cool Orchids, succeeding in an admixture of peat and sphagnum. The plants should be somewhat elevated in potting. Careful ventilation, avoiding draughts, is essential.

With regard to the best method of raising D. grandiflora from seed, the Rev. F. Tymons, of Dub1in, says: "The seed should be sown as soon as it is ripe; but if that does not happen till late in the autumn, it would be safer to postpone the sowing until the following September, or the last week of August. There are two methods of sowing the seed, each of which has its advocates. One of them consists in sowing on living sphagnum, in a pot or pan. The moss must always be kept moist, which may be effected by constant and gentle dewings, as the danger of regular watering, as ordinarily understood, is that the seed would be washed down too deeply. The other plan is to sow on a sod of turf.... or hard peat.... I mean the peat as prepared for fuel. Let it be well soaked in water, and the seed sown thickly on its upper surface. Cover all with a bell glass, and place it in a cool, damp, and shady place. The turf must never become dry, but the spraying of water must be of the gentlest description. A good plan for watering very fine seed is to dip a stiff-haired brush in water, and to draw the hand briskly against it, at such a distance as that only the finest dew reaches the seed. When the seed1ings appear, they must have more air. As soon as they can be handled, they should be pricked off into small pans, or into pots, not less than 4in. in diameter. The compost for the seed1ings, for the first two years, should be somewhat similar to that for mature plants, only that the peat should be considerably finer for an inch or two on the surface, and a much larger proportion of silver sand is necessary. The after-treatment, as regards ventilation, situation, and water, is similar to that for established plants." The same writer warns "persons whose stock is limited to a plant or two, not to be too anxious for seed. One pod on a healthy plant is quite sufficient, as seeding retards the autumn growth and recovery, after the labour of flowering."

D. cornuta (horned-flowered). fl. green, white, and purple, moderately large; spikes 4in. to 6in. long, many-flowered; sepals dissimilar; petals small, oblong, decurved and falcate, with a broad auricle at the base; lip small, spathulate, green, with a large black velvety spot. December. l. lanceolate, erect or erecto patent, acuminate, the lower ones sheathing at the base, and there marked with red spots, the uppermost sessile. Stem green, spotted with red, leafy to the summit. Cape of Good Hope, 1843. (B. M. 4091.) D. grandiflora (large-flowered).* fl. light rose, scarlet, and gold. June and July. l. stem-clasping, alternate, dark green, shining. Stems 2ft. to 3ft. high, four or five-flowered. Table Mountain, 1825. (B. M. 4073.) D. g. Barrellii (Barrell's).* fl. orange - scarlet; lip a lighter shade of the same colour, with crimson veins. 1874. (Gn., Feb. 1882.) D. g. superba (superb). fl. bright scarlet and crimson, veined with pink, over 4in. in diameter. June and July. Stems 1 1/2ft. to 2ft. high, two to eight-flowered. A very handsome form. (Gn., Feb. 1882.) D. macrantha (large-flowered). A garden synonym of D. megaceras. D. megaceras (great-horned).* fl. white, blotched inside with vale purple, large; upper sepal (hood) conical, with an oblique mouth, acute above, slightly curved, undulate; lateral sepals decurved, oblong-lanceolate, with a short recurved spur behind the tip; petals broadly obovate; lip narrowly tongue-shaped, with a revolute tip, glabrous, smooth. August. l. lanceolate, long-acuminate, concave. Stems 1ft. to 2ft. high, robust, leafy. h. 1ft. to 2ft. South Africa, 1880. SYN. D. macrantha, of gardens. (B. M. 6529.) D. polygonoides (Polygonum-like). fl. orange-yellow, or light red or scarlet; spikes very many-flowered; dorsal sepal erect, oblong, sub-acute, very concave, cymbiform, spurred at the base behind; petals much smaller than the sepals, erect, and partially concealed by the upper sepal, 1inear-oblong, tip obtuse and incurved; lip strap-shaped, smooth, flat or convex, obtuse or subacute, slightly constricted above the base. September. l. 1inear-lanceolate, or almost strap-shaped, gradually narrowed to the acuminate point, nearly flat. Stem tall, stout. h. 1ft. to 2ft. Natal, 1879. (B. M. 6532.)