disc] 



Cfje Crntgurg al 38otan». 



418 



short, and the limb fissured in front, and 

 consisting of a single four-lobed lip ; 

 there are four sub-sessile stamens with 

 one-celled anthers. [W. C] 



DISCIFORM. Flat and circular; the 

 same as Orbicular. Also a name given to 

 the chambered pith of such plants as the 

 walnut. 



DISCIPLINE DE RELIGIEUSE. (Fr.) 

 Amaranthus caudatus. 



DISCOC ACTUS. A genus of Cactacece, 

 consisting of three or four species, natives 

 of the West Indies and Brazil, remarkable 

 for having very short flat "fleshy stems, 

 which are only about two inches in height, 

 and from four to six broad, with eight or 

 ten ridges bearing at intervals little 

 bundles "of stiff prickles. The flowers are 

 produced from out of a mass of silky wool 

 and slender spines with which the plant; is 

 crowned ; they have a long narrow tube, 

 the sepals spreading and coloured,the petals 

 white and spreading out very flat, the 

 stamens of different lengths closing up 

 the tube of the flower, and the style 

 thread-like, shorter than the stamens, and 

 divided at the top into five radiating 

 stigmas. The flowers of D. insignis have 

 a very pleasant odour, somewhat resem- 

 bling that of orange flowers; while that 

 of D. alteolens is not so pleasant. [A. S.] 



DISCOCAPNOS. A genus of Fumariacece, 

 distinguished by having the fruit mem- 

 branous, orbicular, flattened, and winged 

 all round. The flowers are nearly as in 

 Corydalis, but with the inner petals united. 

 It is a Cape annual with bipinnate leaves 

 made up of wedge-shaped segments, glau- 

 cous beneath, and climbing by the petioles ; 

 the flowers are in racemes opposite the 

 leaves. [J . T. S.] 



DISCOCARPIUM. A collection of fruits 

 placed within a hollowed receptacle, as in 

 many roseworts. 



DISCOIDAL. Orbicular, with percepti- 

 ble thickness, slightly convex, and a round- 

 ed border. 



DISCOLOR. Parts having one surface 

 of one colour, and the other of another 

 colour. Also any green colour altered by a 

 mixture of purple. 



DISCOPHORA. A genus of Icacinacece, 

 containing a shrub from Guiana, with large 

 smooth leathery shortly-stalked leaves, and 

 axillary racemes of small flowers articulat- 

 ed with the flower-stalks. [J. T. SJ 



DISCOPODIUM. The foot or stalk on 

 which some kinds of disks are elevated. 



DISCOSTEGIA. A name proposed for a 

 few marattiaceous ferns including Ma- 

 rattia alata. [T. M.] 



DISCOSTIGMA. Garcinia. 



DISEASES OF PLANTS. Plants like 

 animals are subject to diseases both func- 

 tional and organic. They arise from vari- 

 ous causes, being often strictly constitu- 

 tional and hereditary ; and frequently, on 



the other hand, induced by bad food, im- 

 perfect nutriment, depraved atmosphere, 

 defect of light, &c. A very important class 

 again arises from the attacks of parasitic 

 animals and Fungi, while others are the 

 direct consequences of injury from ex- 

 ternal agents. Many of the objects of cul- 

 tivation, in which some particular organ 

 or element of the plant is preternaturally 

 developed, are really in a diseased state, 

 the peculiar condition being induced arti- 

 ficially, or, at least, encouraged to supply 

 the wants of man, exactly as the livers of 

 geese are compelled to put on a diseased 

 action to afford materials for the patee. 

 The blanched stems and leafstalks of ce- 

 lery, the swollen steins of kohl-rabi, the 

 enlarged roots of turnips and carrots, &c, 

 are all so many instances of diseased ac- 

 tion compelled to administer to our neces- 

 sities. 



The study of vegetable diseases is essen- 

 tial to good cultivation, for though little 

 can be done towards arresting disease in 

 any individual plant, much may be done, 

 either rationally or empirically, in prevent-* 

 ing the spread of those which are infec- 

 tious or contagious, and more by guarding 

 against those conditions which induce 

 disease. The principal maladies to which 

 plants are subject will be noticed briefly 

 under their respective heads. [M. J. B.] 



DISEMMA. A genus of Passifloracece, 

 closely allied to Pas si flora, hut distinguish- 

 ed from it by the coronet,which consists of 

 an outer row of thread-like processes, and 

 an inner tube with longitudinal plaits. 

 They are shrubs, natives of tropical Aus- 

 tralia, and have entirely the appearance of 

 passionflowers. [M. T. MJ 



DISEPALUM. A Borneo tree forming 

 a genus of Anonacere, remarkable for the 

 sepals and the petals of each series being 

 two only, instead of three, as in the rest of 

 the order. 



DISETTE. (Fr.) A kind of Beet. 



DISK. An organ intervening between 

 the stamens and ovary; it assumes many 

 forms, the most common of which is a 

 ring or scales ; it is apparently composed 

 of metamorphosed stamens. Also the re- 

 ceptacle of certain fungals, or the hyme- 

 nium of others. 



DISOCACTUS. A genus of Cactacece, of 

 which only one species is known. This 

 plant, B. biformis, is a native of Honduras, 

 and forms a weak trailing shrub or bush, 

 with stem and older branches nearly cylin- 

 drical, gradually tapering upwards, and 

 woody ; while the younger branches are 

 broad and flat, with blunt teeth, resem- 

 bling leaves in appearance, but of a succu- 

 lent or fleshy nature. Like most plants of 

 the order, it has no i - eal leaves. The flowers 

 are produced singly from one of the 

 notches at the upper end of the young 

 branches, and are characterised by having 

 only four sepals and four petals, both of a 

 deep pink colour, and about two inches in 

 length, the sepals very narrow and bent 



