AN ENCYCLOPEDIA OF HORTICULTURE. 



329 



ROTATION CROPPING. Cropping by Rotation 

 is a term used in reference to kitchen garden manage- 

 ment. It implies that the ground on which a certain 

 crop is grown shall be planted in Eotation, by another 

 crop of, as far as possible, quite a different character. 

 This system is pretty generally believed in and practised 

 in large gardens; in small ones, there is often neither 

 sufficient space nor variety in the crops annually grown 

 to give an opportunity for changing the situation for 

 each. Where plenty of manure can be added for each 

 crop, it is of not BO much consequence, as additional 

 nutriment will thereby be supplied to take the place of 

 that which the preceding one will have absorbed. It 

 is undoubtedly a good plan to adopt a system of Rotation 

 Cropping, so far as possible, as one sort of vegetable 

 will not, as a rule, require exactly the same constituent 

 parts of the soil to nourish it as another which is of 

 an entirely different nature and habit. In changing 

 crops, it is best to avoid planting any to succeed 

 others which belong to the same Natural Order, as, for 

 instance, the different representatives of the extensive 

 Brassica, or Cabbage tribe. These should be made to 

 follow such crops as Beans, Onions, Peas, Potatoes, &c. 

 It is invariably a good arrangement to grow Peas on 

 land which has, during the previous year, been planted 

 with Celery. Many other instances might be named, 

 but they would not be generally applicable as, for 

 various reasons, ground has to be cropped at certain 

 times and seasons, when it is impossible to pay very 

 much attention to planting under such a system as that 

 indicated. Crops grown for the use of their roots should 

 not follow one another, if it can be avoided ; such, for 

 instance, as Carrots, Parsnips, and other plants of the 

 order Umbellifera}. Onions may follow and be followed 

 by plants of the Brassica tribe. 



ROTHMANNIA. Included under Gardenia (which 

 see). 



ROTTBOELLIA (named in honour of C.F. Rottboell, 

 1727 1797, a Danish botanist). STN. Stegosia. OKD. 

 GramineoB. A genua comprising about eighteen species 

 of often tall, hispid or glabrous, stove or hardy grasses, 

 broadly dispersed over warm regions, one being found 

 in the Orient. Spikelets closely adpressed, pedicellate, 

 inserted in notches on alternate sides of the spike, which 

 is simple, or very rarely twice or thrice divided at the 

 base ; glumes four ; peduncles solitary or fascicled. Leaves 

 flat. A few of the species have been introduced, but 

 they are more curious than beautiful. 



ROTTLERA (of Willdenow). A synonym of Trewia 

 (which see). 



ROTUND, ROTUNDATE. Rounded in outline; 

 usually applied to bodies which are not round them- 

 selves, but only at their ends. 



ROUGE PLANT. See Rivina hnmilis. 



ROULINIA. A synonym of Nolina (which see). 



ROUPALA (said to be the native name in Guiana). 

 Otherwise spelt by various authors Rhopala, Ropala, and 

 Eupala. OBD. Proteatece. A genus of handsome stove, 

 glabrous, or ferruginously-tomentose trees, natives of 

 tropical America. About thirty species have been enume- 

 rated; but they are very difficult to distinguish, entire, 

 toothed, and pinnate leaves being sometimes found on 

 the same tree. Flowers regular, twin-pedicellate, dis- 

 posed in axillary or lateral racemes; perianth cylindrical, 

 the segments eventually becoming recurved at apex. 

 Fruit a hard, obliquely two-valved, shortly stipitate 

 capsule. Leaves alternate, coriaceous, rigid, entire or 

 toothed, undivided or on the sterile branches (of young 

 trees?) pinnate. The species best known to cultivation 

 are described below. They thrive in a compost of peat 

 and loam. Propagation may be effected by cuttings, 

 inserted in sand, under a glass, with bottom heat. 



VoL TIL 



Roupala continued. 



R. Boissieriana (Boissier-s). fl, yellow ; racemes axillary, solitary 

 or twin, sub-sessile, 5in. to 6in. long. /. ovate, Sin. to 4in. long 

 long-acuminate, rounded at base, shortly decurrent into petiolts 

 1m. to 14m. long. New Grenada, 1853. 



R. complicata (folded-leaved), fl. pale rufous, very sweet- 

 scented, in rather loose racemes, Sin. to Sin. long. I. ovate 

 thickly coriaceous, glaucescent, 14in. to 5in. long, lin. to Sin 

 broad, entire or rarely with a few remote or obtuse teeth 

 attenuated-acuminate, broadly rounded at base, decurrent to 

 petioles about lin. long. h. 6ft. to 8ft. Columbia, 1853. 



R. corcovadensis (Corcovado). A synonym of R. Pohlii. 



R. elegans (elegant). I. impari-pinnate, Sin. to 12in. long, nine 

 to twelve-jugate ; leaflets lanceolate, acuminate, serrate, 2in. to 

 4m. long, with mucronulate teeth ; lateral ones falcate, very 

 unequal at base ; terminal ones not larger. Branches slenderly 

 striate. Brazil. 



R. heterophylla (variable-leaved).' * racemes axillary, solitary 

 or twin, sub-sessile, about Sin. long. I. remotely obtuse- 

 toothed, or occasionally entire at base, shining above, the nerves 



Branches twiggy> densely leafy - 



R. media (middle), fl. green ; racemes rufous-tomentose, longer 

 than the leaves. May. I. elliptic, acute and acuminate, mostly 

 simple, but occasionally pinnately trifoliolate, with ovate, entire 

 leaflets, h. 10ft. Guiana, 1823. 



R. montana (mountain), fl. sweet-scented, with yellow or 

 fulvous tomentum ; racemes terminal and axillary, solitary or 

 twin, 5in. to 6in. long, sub-sessile. April. I. elliptic, rigid, 2in. 

 to Sin. long, shortly acute or acuminate, nearly entire, decurrent, 

 on slender petioles, with a few obsolete teeth, h. 10ft. Guiana, 

 1823. 



R. obovata (obovate-leaved). Jr. lin. long, sessile, oblong, sub- 

 falcate. I. obovate, very shortly acuminate, cuneate-attenuated 

 at base, remotely toothed and here and there entire, Sin. to 

 6in. long, 2iin. broad ; petioles lin. long. h. 24ft. Popayan, 

 1855. 



R. Pohlii (Pohl's).* fl. orange-red, clustered in dense, rufous- 

 woolly racemes, which are 6in. to 12in. long, sessile and solitary 

 in the uppermost axils. I. rigid, pinnatisect or entire, ovate or 

 elliptic, acuminate at both ends, irregularly serrate, glabrous, 

 and shining above, woolly-tomentose beneath, h. 6ft. to 20ft. 

 Minas Geraes. (B. M. 6096.) SYN. M. corcovadensis. 



ROTJPELLIA (named in honour of the Roupell 

 family, encouragers of botany). OKD. Apocynacece. A 

 genus comprising two or three species of stove or green- 

 house, glabrous, sometimes climbing, African shrubs. 

 Flowers white or pink, showy, in terminal, dichotomons 

 cymes ; calyx of five oblong or lanceolate segments ; 

 corolla funnel-shaped, with a short tube, an ample cam- 

 panulate throat, and ten processes, united in a ring 

 below; lobes five, broad, twisted. Follicles long, hard, 

 and thick, divaricating, connate at base. Leaves oppo- 

 site, penniveined. R. grata, the only species introduced, 

 is a tall, stove climber, thriving in a compost of fibry 

 loam and peat. It may be increased by means of cut- 

 tings of the young sheets, inserted in sand, under a 

 bell glass, in heat. 



R. grata (agreeably-scented). Cream Fruit-tree, fl., corolla 



white, tinged with pale rose-colour, very fragrant, in dense, 



sessile cymes ; corolla segments broadly obovate ; coronal pro- 



cesses pale rose-colour. May. fr. the Cream Fruit of the 



natives. L nearly 1ft. long, shortly petiolate, oblong-elliptic, 



shortly acuminate, prickly at base, rather thick ; petioles red, 



scarcely dilated at base. Sierra Leone. (B. M. 4466.) 



ROUREA (name not explained ; probably altered 



from the Indian native name of one of the Guiana 



species). SYNS. Canicidia, Robergia (of Schreber). OBD. 



Connaraceoe. A genus comprising about forty-two species 



of stove trees and shrubs ; one is African, and the rest 



tropical American. Flowers small, in axillary, many- 



flowered panicles. Leaves alternate, evergreen, coria- 



ceous, impari-pinnate. R. frutescens, the only species 



introduced, is probably lost to cultivation. 



ROUSS2EACEJB. Included under Saxifragece. 

 ROWAN OR ROAN-TREE. A common name for 

 Pyrus Aucuparia. 



ROXBURGHIA. A synonym of Stemona (which 

 see). 



ROXBURGHIACEJE. A small natural order of 

 twining or erect, half -shrubby plants, natives of tropical 

 Asia and Australia, Japan, and Florida. Flowers herm- 



2u 



