58 It H I 
ter.—Calyx: perianth one-leafed, fleshy, tomentose,half-five- 
cleft ; segments roundish, concave. Corolla: petals five, 
ovate, rounded, concave, fleshy, inserted below the divisions 
of the calyx, and much larger than it. Stamina: filaments 
very numerous, filiform, longer than the corolla, inserted into 
the receptacle, Anthers roundish. Pistils: germ four-cor¬ 
nered, at the bottom of the calyx. Styles four, filiform, 
longer than the corolla. Stigmas blunt. Pericarp: drupes 
four, kidney-shaped, compressed, inserted by the internal 
wedge-formed margin into aconical receptacle, one-celled with 
a fleshy rind, and a buttery soft pulp. Seeds: nuts solitary, 
kidney-shaped, with a brittle shell covered with prickles. 
Kernels solitary, kidney-shaped.— Essential Character .— 
Calyx: half-five-cleft. Petals five. Germ four lobed, supe¬ 
rior. Nuts four, one-celled, one-seeded. 
1. Rhizobolus butyrosis.—This is a tall tree, the trunk of 
which is three feet in diameter: the bark is grey, and the 
wood reddish and compact. It is much branched at 
the top, the branches growing in an opposite direction, and 
the leaves growing exactly opposite also; they are about seven 
inches long, of a bright green, the leaflets being entire, oval, 
and pointed. The flowers grow in large bunches at the ex¬ 
tremities of the branches, and are of a white colour, large, 
with numerous stamens, and yellow anthers.—It is a native 
of Guiana, and is cultivated at Cayenne, where it flowers in 
the month of July. 
2. Rhizobolus tuberculosus.—-This differs from the pre¬ 
ceding in having the leaves downy beneath: they are also 
thicker; and the fruit is larger, and tuberculate; juiceless, 
and without the butyraceous quality of the former.—It grows 
in Guiana, and produces its fruit in July. 
RHIZOMA, an appellation bestowed, by several late 
authors, on the tuberous caudex, or body, of some roots; as 
that of Iris Germanica, and many other of the natural order 
of Ensatce of Linnaeus and Gawler. See Root. 
RHIZOMORPHA, [so called from its resemblance to the 
branching fibrous roots of various plants,] a genus of fungi, 
established by Persoon, in his Synopsis, 704. Generic Charac¬ 
ter. Creeping, rigid, smooth, with a villous pith. Persoon 
enumerates three species: R. subcorticalis, subtirranea, 
found among wet timber-work, in mines; and setiformis, 
found among dead leaves in woods. They are all, to us, 
very obscure, and perhaps imperfect productions. 
RHIZOPHORA, s. [from pi£«, a root, and peptu,Gr. to bear.] 
In botany, a genus of the class dodecandria, order mono- 
gynia, natural order of holoracese, caprifolia, (Juss.) Generic 
Character.—.Calyx: perianth one-leaved, four-parted or many- 
parted, patulous; segments oblong, acuminate, permanent. 
Corolla : petals four or more, oblong, rather shorter than 
the calyx. Stamina: filaments scarcely any, alternately 
shorter; anthers four to twelve, small, acuminate. Pistil: 
germ superior, roufidish; style awl-shaped, semi-bifid, 
grooved on each side; stigmas acute. Pericarp fleshy, sub- 
ovate, inclosing only the base of the seed. Seed single, 
club-oblong, acuminate, fleshy at the base. The stamens 
differ in number, as do the calyx and corolla.— Essential 
Caracter. —Calyx four-parted. Corolla four-parted. Seed 
one, very long, fleshy at the base.—All the species 'of this 
genus are maritime trees, extending far and wide by their many- 
times-rooting branches, which are frequently opposite. They 
are all natives of the East Indies, Rhizophora mangle is 
found in the West Indies also. 
1. Rhizophora conjugata.—Leaves evate-oblong, bluntish, 
quite entire, calyxes sessile, fruits cylindric-subulate. 
2. Rhizophora gymnovhiza. — Leaves ovate-lanceolate, 
quite entire, root placed upon the ground. This tree is above 
the middle size, with a lofty straight trunk : the bark is thick, 
cloven, of a brown-red colour: with many large bowed 
roots spreading upon the cone that is covered with sea-water. 
Calyx from ten to thirteen-parted. 
Gaertner thus describes the fruit. “ The calyx when ripe 
is coriaceous, thick, divided into twelve or fourteen parts, 
which are linear-acuminate, and curved in: shell of the seed 
fleshy-coriaceous, inversely parabolical, regularly truncate 
at top, detached on all sides, wholly immersed in the belly 
R H 1 
of the calyx. Embryo inverted, of a greenish bay colour; 
cotyledons four, convex on one side, ‘angular on the other, 
leafy, twisted together, converging into a globe, grass green : 
radicle detached every way from, the integuments, clavate- 
cylindrical, obscurely angular, very smooth, shining, from 
three inches to a foot and more in length, bluntish or acu¬ 
minate.” . , 
The bark of this tree is very useful in dying rufous or 
chesnut colour; which is easily changed into a very fine 
permanent black. 
3. Rhizophora candel.—Leaves obtuse, peduncles bigemi¬ 
nate, longer than the leaf; fruits awl-shaped. 
4. Rhizophora mangle, or the mangrove tree.—Leaves 
acute, fruits subulate-clavate. The mangrove tree commonly 
attains the height of fifty feet; the wood is white, but 
becomes red when macerated in water; the bark is thick and 
rust-coloured. Leaves ovate, shining, deep green on the 
upper surface, on the lower yellowish green with blackish 
dots, from three to six inches long. The flowers are com¬ 
monly without scent, but sometimes they" are a little sweet. 
Calyx deeply four-cleft, yellowish. Petals four, white. 
Anthers constantly eight, and very caducous. 
Jacquin has given an interesting description of the fruit, 
and the extraordinary mode in which the seed germinates. 
“ The fruit of this tree,” says Browne, “ genninates within 
the cup, and grows from the top downwards, until it acquires 
a due degree of weight and perfection: then it falls off; and 
as the root is always thickest, and hangs lowest, it drops in 
that direction, and is thus received in its natural position in 
the mud below ; the leaves immediately unfold, and in a few 
minutes a perfect plant is seen, sometimes of ten or twelve 
inches in length, which soon begins to shoot its roots, and 
push its growth like the parent stem, for the germ is fre¬ 
quently a foot in length before it falls, and has always two 
leaves at the top; but these are folded up, and inclosed 
within the cup whilst it continues on the tree.” 
The Mangrove is generally found on the borders of the 
sea, in w hose waters alone it seems to thrive; and there only 
in such places as have a soft and yielding bottom. Its larger 
branches frequently emit soft and weakly appendicles, that 
have the appearance of so many slender leafless branches, 
and bend always downwards: but as these are softer, and 
furnished each with a large column of a lax spongy pith in 
the centre, they grow more luxuriantly than the other parts 
of the tree, and reach the mud in a short time, where they 
throw out a numberless series of slender fibres, which in 
time become roots, to supply the stem more copiously with 
nourishment, whilst they become so many props or limbs to 
the parent tree. Thus it continues to enlarge its bulk, as its 
weight increases, or its branches spread; these constantly 
throwing out new appendicles as they multiply their shoots, 
and so forms those interwoven groves we so frequently meet 
with on the sea shore in the tropical climates, which serve 
to stop the mould that is constantly washed down by those 
rapid floods that come from the inland parts, and thereby in 
time turn what might have otherwise continued useless ponds 
or open creeks, into rich and fertile fields. 
The trunk of the mangrove seldom grows to any consider¬ 
able thickness, but the wood is very tough and hard, bears 
the water well, and is much used for knees and ribs in long¬ 
boats, and other small-craft. The American oystersfeed on 
the lower branches, which has given rise to the fabulous 
account of the growth of this shell-fish on trees, as a fruit. 
The bark is more excellent for tanning leather than oak- 
bark. 
According to Dampier, there are three sorts of Mangrove 
trees, black, red, and white. The white never grows so 
big as the other two, neither is it of any great use. Of the 
young trees they make handles for oars, for it is commonly 
straight, but not very strong. 
5. Rhizophora cylindrica. — Fruits cylindrical, blunt. 
This much resembles the second species. 
6. Rhizophora sexangula.—Leaves ovate-lanceolate, oppo¬ 
site, fruits hexangular, petals ten, stamens twenty. 
RH1ZUS, a po/t of Cappadocia, near Trebizond, be¬ 
tween 
