AN ENCYCLOPADIA 
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 Rotation, 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 so 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 Umbellifere. Onions may follow, and be followed 
by plants of the Brassica tribe. If similar crops have 
of necessity to succeed each other, the ground should 
be well dug or trenched and manured between the 
times of removing the one and planting another. 
ROTHMANNIA. Included under Gardenia (which 
see). 
ROTTBOELLIA (named in honour of C. F. Rottboell, 
1727-1797, a Danish botanist). Syn. Stegosia. ORD. 
Graminee. A genus 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 appressed, 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. 
ROTUND, ROTUNDATE. Rounded in outline; 
usually applied to bodies which are not round them- 
selves, but only at their ends. 
ROUGE PLANT. See Rivina humilis. 
-ROULINIA. A synonym of Nolina (which see). 
 ROUPALA (said to be the native name in Guiana). 
Otherwise spelt by various authors Rhopala, Ropala, and 
Rupala. ORD. Proteacew. 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. IIL 
- Pyrus Aucuparia. 
ROXBURG: 
Roupala—continued. . 
R. Boissieriana (Boissier’s), /l, yellow ; racemes axillary, solita 
or twin, sub-sessile, 5in. to 6in. ong. l. ovate, 3in. to 4in. erg 
long-acuminate, rounded at base, shortly decurrent into petioles 
lin. to 1żin. long. New Grenada, 1853. ` 
R. complicata (folded-leaved). fl. pale rufous, very sweet- 
scented, in rather loose racemes, Zin. to Sin. long, l ovate, 
thickly coriaceous, glaucescent, gn to Sin. 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). l tupart-pinnate, 8in. to 12in. long, nine 
to twelve-jugate ; leaflets lanceolate, acuminate, serrate, 2in, to 
4in. long, with mucronulate teeth; lateral ones falcate, very 
unequal at base; terminal ones not larger. Branches slenderly 
striate. Brazil. 
R. heterophylla (variable-leaved).* f racemes axillary, solitary 
or twin, sub-sessile, about 3in. long. J. remotely obtuse- 
toothed, or occasionally entire at base, shining above, the nerves 
elevated on both surfaces, Branches twiggy, densely leafy. 
Brazil. (R. G. 1863, 402.) 
R. media (middle). M. green ; racemes rufous-tomentose, longer 
than the leaves, May. Zl. elliptic, acute and acuminate, mostly 
—— but occasionally pinnately trifoliolate, with ovate, entire 
leaflets. h. 10ft. Guiana, 1823. 
R. montana (mountain). jl. sweet-scented, with yellow or 
fulvous tomentum ; racemes terminal and axillary, solitary or 
twin, Sin. to 6in. long, sub-sessile. April. Z. — rigid, 2in. 
to din. long, shortly acute or acuminate, nearly entire, decurrent, 
on slender petioles, with a few obsolete teeth. h. 10ft. Guiana, 
R. obovata (obovate-leaved). fr. lin. long, sessile, oblong, sub- 
faleate. l. obovate, very shortly acuminate, cuneate-att ted 
at base, — toothed and here and there entire, 3in. to 
— long, 24in. broad; petioles lin. long. h. 24ft. Popayan, 
Poblii (Pohl’s).* fl. orange-red, clustered in dense, rufous- 
— — ic are 6in, to 12in, long, sessile and solitary 
in the uppermost axils. l. rigid, pinnatisect or entire, ovate or 
elliptic, acuminate at both ends, irregularly serrate, glabrous, 
and shining above, woolly-tomentose beneath. A. 6ft. to 20ft. 
Minas Geraes. (B. M. 6095.) SYN. R. coreovadensis. 
ROUPELLIA (named in honour of the Roupell 
family, encouragers of botany). Orp. Apocynacee. A 
genus comprising two or three species of stove or green- 
house, glabrous, sometimes climbing, African shrubs. 
Flowers white or pink, showy, in terminal, dichotomous 
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 shoots, inserted in sand, under a 
bell glass, in heat. s 
R. (agreeably ted). Cream Frnit-tree. fl., corolla 
white, tinged with pe 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 — — — — ———— 
inate, pri a , ral : $ 
— y dilated at Nase.” Sierra Leone. (B. M. jade) 
ROUREA (name not explained; probably altered 
from the Indian native name of one of the Guiana 
species). Syns. Canicidia, Robergia (of Schreber). Orp. 
Connaracew. 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. 
ROUSSÆACEÆ. Included under Savifragew. 
ROWAN OR ROAN-TREE. A common name for 
HIA. A synonym of Stemona (which 
see). 
ROXBURGHIACEZ. A small natural order of 
twining or erect, half-shrubby plants, natives of tropical 
Asia and Australia, Japan, and Florida. Flowers herm- 
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