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AN ENCYCLOPZADIA OF HORTICULTURE. . 291 
Rhizophora—continued. Rhodites—continued. 
to take possession of the mud, in advance of their parent above are natives of Europe. For further information, 
stems” (Dr. Wm. Hamilton, in the “ Pharmaceutical see Rose-galls. 
Journal”). R.Mangle has been introduced to this country, 
but is difficult to cultivate. 
RHIZOPHOREZ. A natural order of usually quite 
glabrous trees and shrubs, with terete branchlets swollen 
at the nodes, almost wholly tropical, and to a great 
extent littoral. Flowers usually hermaphrodite, axillary, 
disposed in cymes, panicles, spikes, or racemes, rarely 
densely clustered or solitary, small or rather large, bi- 
bracteolate or ebracteolate; calyx tube more or less 
_adnate to the ovary, rarely free; limb three to fourteen- 
lobed or entire, persistent; petals as many as the calyx 
lobes, usually small, concave or involute, and embracing 
the stamens, notched, bifid, or lacerate, rarely entire, 
conyolute or inflexed in bud; stamens twice, or three or 
four times, as many as the petals, rarely equal in 
number; ovary usually inferior, two to five (rarely six) 
celled. Fruit usually coriaceous, crowned with the calyx 
limb, indehiscent or rarely septicidal, one-celled and one- 
seeded, or with two to five one-seeded cells. Leaves 
opposite and stipulate, rarely alternate and exstipulate, 
petioled, thickly coriaceous, usually quite entire, in a few 
cases sinuate-crenulate or serrulated; stipules inter- 
petiolar, very caducous. The wood of Rhizophora Mangle 
is described as edible, and when fermented produces a 
light wine. The order comprises seventeen genera, and 
about fifty species, none of which are of horticultural 
value. Examples: Haplopetalum, Rhizophora. 
_RHIZOS. This term, used in Greek compounds, 
signifies a root; e.g., Rhizophora. 
RHODAMNIA (from rhodamnus, a small branch; 
in reference to the size of the plants). Syn. Monozora. 
ORD. Myrtacee. A genus of stove or greenhouse shrubs 
or small trees. Twelve species have been enumerated ; 
of these, three are natives of Eastern or tropical Australia, 
and the regt of tropical Asia. Flowers often small; calyx 
tube ovoid or sub-globose; limb of four persistent lobes 
or segments; petals four, spreading ; pedicels short, some- 
times very short, fasciculate in the axils, or shortly and 
loosely racemose; bracteoles small, caducous. Leaves 
opposite, ovate or lanceolate, three-nerved or tripli- 
nerved, often hoary or downy beneath: The only species 
introduced is often erroneously classed under Eugenia. 
For culture, see Myrtus. 
trinervia (three-nerved). fi. white; peduncles slender, axil- 
lary, three together in a cluster, or on a short, common peduncle, 
each with one or rarely three flowers. May. l. ovate-oblong or 
ovate-lanceolate, acuminate, glabrous and much reticulated 
above, prominently three-nerved from the base, beneath, as well 
as on the young shoots and inflorescence, velvety-pubescent. 
Australia, 1 A tall nhouse shrub or small tree. (B. M. 3223, 
under name of Eugenia trinervia.) 
RHODANTHE. Included under Helipterum 
(which see). 
RHODIOLA. Included under Sedum (which see). 
RHODITES. A genus of Gall-flies (Cynipide), all 
the known species of which, viz., six European and 
four American, make galls on Roses, but on no other 
plants, with the exception of R. radicum, one of the 
American forms, which is said also to gall the roots of 
Raspberries, and of Blackberries or Brambles. 
R. Rose produces the well-known Bedeguar Gall on 
various kinds of Roses; R. spinosissime makes galls 
of very varied form on twigs, leaves, and fruits of 
Rosa spinosissima and R. canina; R. Eglanterie makes 
smooth, round galls, like small peas, on leaves of _ Rosa 
canina and R. rubiginosa; R. centifolie makes similar 
galls on Rosa centifolia; R. rosarum causes the growth 
of small, round leaf-galls, each decked with a few long 
prickles, on various kinds of Roses; and R. Mayri forms 
galls on leaves and branches of Rosa canina. All the | 
RHODO. This term, used in Greek compounds, sig- 
nifies red; e.g., Rhodochiton, Rhodostachys. 
RHODOCHITON (from rhodo, red, and chiton, a 
cloak; in reference to the large, coloured calyx). ORD. 
Scrophularinee. A monotypic genus. The species is an 
elegant, greenhouse herb, with the petioles and pe- 
duncles usually twisted and climbing. For culture, see 
Maurandya. 
R. volubile (twining).* ji. on axillary, elongated pedicels ; cal 
pale reddish, ample, broadly campanulate, semi-five-fid ; coro! 
dark blood-colour, rather large, with five erecto-patent lobes. 
June. Jl. alternate, cordate, acuminate, with a few acute teeth, 
— glandular-puberulous. k, 10ft. Mexico, 1833. (B. M. 
7; BR.: 1755; S. B. F. G. ser. ii. 250.) 
RHODOCISTUS BERTHELOTIANUS. A sy- 
nonym of Cistus candidissimus (which see). 
RHODOCOMA. A synonym of Restio (which 
see). 
RHODODENDRON (an old Greek name, from 
rhodos, a rose, and dendron, a tree; in allusion to the 
rose-red flowers of many of the species). Rose Bay. 
Azalea and Rhodora are merged, by the authors of the 
“Genera Plantarum,” into this genus, but for garden 
purposes they have been kept distinct in this work. 
ORD. Ericacee. A large and popular genus of highly 
ornamental, glabrous, pubescent, tomentose, or lepidoted, 
stove, greenhouse, or hardy shrubs, rarely trees. The 
species, which number upwards of 100, are natives of the 
mountains of Europe, Asia, the Malayan Archipelago, and 
North America, often gregarious, being copiously found 
on the Himalayan mountains. Flowers usually large, often 
disposed in terminal, many or few-flowered, sometimes sub- 
racemose corymbs, rarely axillary or solitary; calyx vari- 
able, five-sepaled, five-toothed, patelliform, cup-shaped, or 
obsolete, coriaceous or leat-like, persistent; corolla vari- 
able, often funnel-shaped or bell-shaped, rarely tubular, 
salver-shaped, or sub-rotate; limb more or less oblique, 
five (rarely six to ten) lobed or rarely parted, very rarely 
sub-bilabiate, the lobes imbricated; stamens eight to ten, 
rarely five or twelve to eighteen, more or less unequal, 
sometimes spreading; filaments subulate-filiform or short 
and thigk, usually pilose or bearded at the base. Cap- 
sules short or elongated, woody, five to twenty-celled. 
Leaves alternate, often clustered at the tips of the branch- 
lets, entire, coriaceous, rarely membranous, annual or 
biennial. a 
Rhododendrons may justly be classed amongst the most 
beautiful and attractive of evergreen, flowering shrubs. 
Their foliage is at all times attractive, and the flower- 
trusses, which vary much in size with the species or 
variety, are usually borne in the greatest profusion when- 
ever the plants succeed. Amongst outdoor shrubs, none 
are more showy when in flower than the gorgeous varie- 
ties and hybrids raised from R. ponticum. ‘This species 
itself has now been so generally superseded by varieties 
or hybrids, that it need no longer be grown extensively, 
except for covert planting, and for the supply of stocks 
whereon to graft the superior forms. Some of the’grandest 
indoor plants, where space can be allowed them to develop, 
are specimens of the Himalayan species, many of which 
have flowers highly perfumed, in addition to their other 
good qualities. Of late years, numerous hybrids have been 
raised, by using, for crossing and inter-crossing, several 
of the species and hybrids which have been from time 
to time obtained. These are all beautiful, and well 
adapted for culture in small pots, for greenhouse deco- 
ration. They have always been much valued, and seem 
deservedly to be fast increasing in popularity. 
Propagation. There are several methods by one or 
more of which the species, hybrids, and varieties of 
