484 



THE DICTIONARY OF GARDENING, 



Disa continued. 



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. I. 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, linear-oblong, tip obtuse and in- 

 curved ; lip strap-shaped, smooth, flat or convex, obtuse or sub- 

 acute, slightly constricted above the base. September. I. linear- 

 lanceolate, or almost strap-shaped, gradually narrowed to the 

 acuminate point, nearly flat. Stem tall, stout A. 1ft to 2ft. 

 Natal, 1879. (B. M. 6532.) 



DISANDRA. A synonym of Sibthorpia (which see). 

 DISBUDDING. By this term is meant the removal 

 of superfluous buds, flowers, or shoots, in the early stages 

 of growth, from fruit or other trees, in order to divert 

 the sap into those which are stronger, and required to 

 remain either for the production of branches, flowers, or 

 fruits of superior quality. It is of necessity very largely 

 practised with fruit-trees, under glass, that have to be 

 kept within a limited area, and where the crop of fruit 

 and continued vigour of the trees are annually matters 

 of very great importance. The branches of Figs, Peaches, 

 and Vines, amongst many others, are each year so full of 

 young shoots in spring, or at other seasons, when started 

 into growth, that if all were allowed to remain, the 

 result would be a dense thicket of useless branches. 

 Disbudding should always be performed with judgment, 

 and only by those who understand it, as irreparable 

 damage may easily be caused by the uninitiated. The 

 operation should be commenced as soon as the young 

 buds or shoots are large enough to pinch out with the 

 finger and thumb, and the process should be frequently 

 repeated, rather than remove too much at a time. Many 

 plants may, with advantage, be disbudded occasionally to 

 thin the branches, for admitting more light and air, or 

 for inducing a more compact habit. Disbudding of flowers, 

 where crowded, if carefully performed when in an early 

 stage, may also be recommended in some cases. 



DISCARIA (from diskos, a disk; the disk being 

 large and fleshy). SYN. Tetrapasma. OBD. Rhamnea. 

 An interesting genus of about thirteen species of spiny 

 shrubs. One is a native of Australia, another of New 

 Zealand; all the rest are extra-tropical South American. 

 They are closely allied to Colletia (which see for cul- 

 ture). 



D. australlfl (Southern), fl. yellow ; racemes short, many- 

 flowered, rising from beneath the spines. May. 'I. few, oppo- 

 site, obovate, minute, quite entire, pubescent. Branches almost 

 leafless, pubescent ; branchlets simple, spiny. A. 2ft. Australia, 

 1824. A greenhouse evergreen. SYN. Tetrapasma juncea. 

 D. sorratifolia (saw-leaved). fl. greenish - white, in axillary 

 tufts, very fragrant. June. I. opposite, shining, bright green. 

 A. 6ft. to 10ft. Branches green, like those of a broom, spiny. A 

 capital subject for pot culture, or as a plant for a conservatory 

 wall. (G. C. n. s., vi. 324.) SYN. Colletia serratifolia. 

 D. Toumatou (Touinatou). Wild Irishman, fl. white, Ain. in 

 diameter, apetalous ; pedicels and calyx minutely downy ; calyx 

 tube short, obscure; lobes four or five, broadly ovate; disk 

 broad, with a narrow upturned edge. June. I. small, fascicled, 

 in the axils of the spines, absent in old plants, linear or obovate- 

 oblong, obtuse or retuse, smooth or pubescent, quite entire or 

 serrate. A. 15ft., in sub-alpine localities. New Zealand, 1875. 

 Greenhouse. 



DISCHIDIA (from dischides, twice-cleft; referring 

 to the bifid segments of the corona). OBD. Asclepiadeae. 

 A genus of stove evergreen perennial trailers. There 

 are about twenty-four species, natives of the East Indies, 

 Malayan Archipelago, and tropical Australia. Flowers 

 white or red, small, sub-umbellate. Leaves opposite, 

 roundish, thick, fleshy. Stems rooting at the joints. 

 For culture, see Hoya. 



D. benghalensis (Bengalese). fl., corollas small, urceolate ; 

 umbels few-flowered, from alternate axils, on short peduncle.. 



Dischidia continued. 



September. I. oblong-lanceolate, two-edged, flat. India, 1818. 

 (B. M. 2916.) 



D. nummularia (Moneywort-leaved). Jl. very small, in little 

 sessile, axillary or interpetiolar clusters ; calyx segments minute, 

 corolla under one-and-a-half lines long ; tube inflated ; lobes 

 narrow, longer than the tube ; corona segments subulate. 

 August. I. on very short petioles, nearly orbicular, thick, fleshy, 

 not exceeding Jin. in diameter, h. 6in. Queensland. A suc- 

 culent milky-juiced epiphyte, more or less mealy-white. 



DISCOID. When, in Composite, the ray-florets are 

 suppressed, the head of flowers is said to be Discoid. 



DISCOLOR. Parts having one surface of one 

 colour, and the other of another. 



DISEASES. Many plants are subject to no Disease, 

 although they may be particularly so to insect pests. 

 Others, again, are susceptible to Disease at any stage of 

 growth, and when it is often very diflBcnlt to know the 

 cause from which the evil proceeds. Canke.% Gumming, 

 and Mildew are destructive Diseases to fruit-trees and 

 plants. The cause of the first cannot be traced in many 

 cases; while in others it may be discovered too late for 

 applying a remedy, even if this were practicable. Gum- 

 ming and Mildew are caused by Fungi. The progress 

 'of Disease in plants may often be stopped if measures 

 are taken, when it is first detected, to find and, if possible, 

 remove the cause. When once established, it is far more 

 difficult to cure, or even check; fatal results being often 

 the ultimate consequence. Diseases being caused by 

 forces acting apparently under such opposite conditions 

 in similar or- different plants, it is impossible to give 

 instructions for their prevention generally. A cold and 

 undrained soil, or that which is excessively rich, sudden 

 changes x>f temperature, improper pruning, draughts, or, 

 on the other hand, a too close or moist atmosphere, with 

 many other like conditions, tend to promote Disease, and 

 should be always guarded against Diseases arising from 

 the growth of a fungus on any parts of plants, are often 

 greatly encouraged by a warm, moist atmosphere. Some 

 of this description are amongst the most destructive, 

 and, as a rule, it is very difficult or impossible to 

 effect a cure, when they become established. The fungi 

 which are more or less superficial in their growth that 

 is to say, live on the surface of the tissues may be 

 checked by dusting with sulphur, &c. ; those, like the 

 Potato Disease (Peronospord), for instance, which send 

 their threads into the body of the host plant, cannot 

 be destroyed by any such means. 



DISEMMA. This genus is now merged into Passi- 

 flora (which see). 



DISK. Any organ between the stamens and ovary, 

 generally scaly or annular. The central tubular flowers 

 of Composites are also called the Disk. 



DISOCACTUS (from dis, two, isos, equal, and Cactos; 

 in allusion to the number of the sepals and petals being 

 constantly twice two). OBD. Gacteaa. This is now united 

 with Phyllocactus, from the other members of which genus 

 it only differs in its fewer sepals and petals. 



DISFORUM (from dis, double, and poros, a pore ; 

 application not stated). Including Prosartes. OBD. 

 Liliacece. A genus consisting of about a dozen species 

 of perennials, natives of North America and the moun- 

 tains of tropical Asia. Flowers solitary or clustered, at the 

 tips of the branches. Leaves alternate, sessile or shortly 

 stalked, ovate or lanceolate. Stems creeping, spreading, 

 or erect from an underground rhizome, sparingly branched, 

 leafy. The species thrive in a moist peaty border, and 

 prefer partial shade. Propagated by seeds, or by dividing 

 the plants in spring, before active growth commences. 

 D. fulvum (tawny). A synonym of D. pullum. 

 D. Hookerii (Hooker's), fl. greenish, one to six; segments 

 spreading above, iin. long, narrowed at base ; stamens nearly 

 equalling, or a little exceeding, the perianth. I. ovate, mostly 



niy cordate, rough on the margins and nerves beneath. 

 t to 2ft. California. 



