seed, which is contained within the proper integuments, 
consisting of albumen, with the vitellus, when present, 
and embryo. 
Nuts. — Individual seeds contained in a bony pericarp, of a hard 
and bony, though sometimes of a leathery texture, not 
opening spontaneously, or if opening, not into more 
than two valves. It is exemplified in the Filbert and 
Chestnut. 
One ordate.— Heart-shaped leaves, when rounded at the apex. 
Oblique. — When one part of the leaf is vertical, the other 
horizontal. 
Obovate. — Egg-shape, with the broad end uppermost. 
Obtuse. — When any part forms the segment of a circle, and is 
rounded. 
Ocheea. — The ochrea is a membranous sheath, being appa- 
rently, a modification of the bracte, situated at the 
base of the petiole, and at the same time, surrounding 
the stem, as in Polygonum. 
Offset. — The offset is a short lateral branch, in some herba- 
ceous plants, terminated by a cluster of leaves, and 
capable of taking root, when separated from the parent 
plant, as in Sempervivum. It differs but little from 
the runner. 
Omphalqdium. — The central point of the hilum, where the 
nourishing vessels enter the seed, is by Turpin, called 
the Oinphalodium. 
Operculum.— -The lid which covers the orifice of the urn of 
the mosses, is the operculum. 
Ovary. — The ovary is the lower extremity of the pistil, enclo- 
sing the ovula in its cavity or cavities, and supporting 
the style and stigma. In its attachment it is sessile, 
as in Arbutus, or stipitate, as in the Poppy, ff it ori- 
ginates below the calyx, it is said to be inferior, as in 
the apple ; if above, or rather within the calyx, it is 
said to be superior, as in Primula. Yet some botanists 
contend that it is always superior; and when it §eems 
otherwise, it is only because the lower portion of the 
calyx, is so intimately incorporated with the ovary as 
to seem to be part of it, (Ventenat,) as in the case of 
the apple and pear. Its figure is globular or egg- 
shaped, or oblong, or compressed, as in the Vetch. 
In its structure it is simple, that is, containing only a 
singde cell, as in the pea and bean; or compound, that 
is, containing two or more cells, as in Euphorbia. 
That portion of the ovarium in which the ovula origi- 
nate is called the placenta. It is either a part or the 
whole of one angle, of each cell, to which the ovula 
are attached, either immediately, or through the in- 
tervention of a small cord, called the umbilical cord. 
Ovate. — When the length of a leaf is greater than the breadth, 
with both extremities rounded ; but- the base much 
broader than the apex. 
Ovate-lanceolate. — Partaking of the ovate and lanceolate 
figure. 
Ovula. — The ovula are small, semi-pellucid, and pulpy bodies, j 
issuing from the placenta, and changing gradually into I 
seed. 
Palmated. — When a leaf is divided nearly down to the middle 
into several segments. 
Panicle.— The panicle is an assemblage of flowers, supported 
upon a primary and terminal peduncle or axis, that is 
irregularly divided into secondary peduncles, which are 
sometimes again subdivided into tertiary peduncles 
or pedicles. It is exemplified in B vomus urvensis and 
Avena fiavescens, and may be regarded as resembling 
a sort of loose spike. 
Panduriform.-— Fiddle-shaped. Oblong, broad at two ex- 
tremities, and contracted in the middle. 
Papilionaceous Flower.— Sometimes the 'petals of a tetr&- 
petalous corolla are irregular, and disposed so as to 
exhibit a slight resemblance to a butterfly, in which 
case the flower is said to be papilionaceous, and is ex- j 
emplified in that of the pea and bean, the petals of ; 
which, and of all similar flowers, are so peculiar in 
their form or position as to have received distinct ap- 
pellations. The upper petal, which is generally large, 
and furnished with an erect border, is denominated the 
standard. The lower petals which is situated opposite 
to the standard, and hollowed out in the form of a boat, 
is denominated the keel; and the two remaining 
petals, which are situated in an opposite position, one 
on each side of the keel, are denominated wings. If 
the keel or boat is composed of two distinct pieces, as 
is sometimes the case, then the papilionaceous flower 
is quinquepetalous. 
Papilla — The Papillae are minute, transparent, and elevated 
points, emerging from the cuticle, of the leaf or flower, 
and filled with a peculiar fluid. They are the utricular 
glands of Guettard, and are well exemplified as they 
occur on the leaves of the Ice Plant. 
Pappus. — This term is sometimes employed to denote the down 
which many botanists regard as the proper calyx of 
compound flowers. 
Parasites. — There are certain plants, many of them Phse- 
nogamous, but more, perhaps, Cryptogamous, that 
will vegetate neither in the earth nor water, but on 
certain other plants, to which they attach themselves 
by means of roots that penetrate the bark ; or into the 
interior of which they insinuate themselves in a more 
mysterious way, and from the juices of which they do 
often, but not always, derive support. 
Parenchyma. — The Parenchyma of some writers seems to 
imply merely what is otherwise denominated cellular 
tissue. We prefer that acceptation of it by which it 
is made to be equivalent to the term pulp, that is, a 
cellular tissue, whose cells are filled with a chromule, 
whether green, as in the interior of the leaf, or colour- 
less, as in the interior of a ripe apple. 
Paries. — The wall, or external boundary of any containing 
organ, is its paries ; as the wall or paries of the ovary 
containing the incipent ovula or ripened seeds. 
Partitions.— Partitions are the Septa or dissepiments by 
which an ovary is often divided in‘o several cells 
bearing-placentae, as in the genus Iris. All dissepiments 
are vertical. They cannot be horizontal, because they 
cannot have a direction different from that of the car- 
pella. They are equal in number to the carpella out 
of which the pistil is formed. A single carpellum 
can have no dissepiment. 
Pectinate. — When the segments of a leaf are very narrow, 
linear and parallel like the tooth of a comb, they are 
called pectinate. 
Pedicles. — The ramifications of the main peduncle, when it 
has any, take the name of Pedicles. 
Peduncle. — The Peduncle is a flower stalk issuing from the 
stem or branch, and supporting a flower or flowers, 
but not leaves. 
Pellicle. — Any thin filmy membrane is a Pellicle; but Gaert- 
ner applied the term to the fine epidermis that covers 
the surface of some seeds, as those of Salvia verbenaca. 
Peltate. — When the petiole is inserted into the disk of a leaf. 
Pendant. — When the whole leaf droops. 
Perennials. — When they last for more than two years. 
Perfect Flowers. — When stamens and pistils, are both, as 
usual, in one flower, it is called perfect, united or 
hermaphrodite, as in Rosa canina, Papaver somni/e- 
rum, and most plants. 
Perfect Plants.— Plants furnished with the full complement 
of parts and organs common to vegetables in general, 
are said to be perfect. They are said also to be 
phsenogamous, as being furnished with conspicuous 
flowers ; because conspicuous flowers are the glory of 
the plant, and in many plants they are wanting. 
Hence, if any plant is deficient in one or more of the 
parts or organs common to vegetables in general, such 
plant is said to be imperfect. 
