Dioecious Plants — Plants having their male or staminiferous 
flowers on one individual, and their female or pistili- 
ferous flowers on another, are said to be dioecious — 
that is, to have their flowers in two houses. They 
are exemplified in Hemp, Spinach, Hops. 
Digitate. — When several, usually seven leaflets, proceed from 
the summit of a common foot-stalk, and have the ap- 
pearance of fingers. 
Dipetalous. — Corolla formed of two petals. 
Diploe. — The interior parenchyma that lies between the upper 
and under layers of the net work of the leaves, is by 
some botanists called the diploe — a term borrowed from 
the Anatomical nomenclature of the zoologist, signi- 
fying the cellular substance that is lodged between the 
tables of the flat bones. 
Disk. — In the language of the followers of Linnaeus, the disk 
denotes the central portion of the receptacle of such 
compound flowers as have florets of the ray different 
in shape from those of the centre. In fhe language 
of the followers of Jussieu it denotes certain peculiar 
substances situated, for the most part, between the 
base of the ovary and the base of the stamens, and in 
the form of a fleshy ring, or of fleshy lobes as in La- 
mium, in which case it is hypogynous ; or assuming the 
form of a cup, and adhering to the calyx, as in Amyg- 
dalus, in which case it is perigynous ; or surmounting 
the summit of the ovary, as in the Umbelliferae and 
Composite, in which case it is said to be epigynous. 
Lind. Introd. 137- 
Dissepiments. — Dissepiments are the partitions that form and 
separate the several cells of the compound fruit or 
ovary. 
Distichous. — Applied to stems, leaves, &c. when they spread 
in two horizontal directions. 
Divergent Layers. — The divergent layers, proper to exo- 
genous plants, they intersect the concentric layers in 
a transverse direction, proceeding from the centre to 
the circumference of the stem or branch, and constitute 
a considerable proportion of the wood, as may be seen 
on a horizontal section of the Fir or Birch, or of al- 
most any woody plant, under the form of lines, diver- 
ging like the radii of a circle. 
Dolabriform. — Hatchet-shaped, leaves compressed, with a 
very prominent dilated keel, and a cylindrical base. 
Drupe. — The drupe is a fruit, consisting of a soft and pulpy 
pericarp, that encloses a nut, as the peach or cherry. 
Ducts. — The Jausses trachdes of Mirbel, the tubes corpus- 
culifkres of Dutrochet, the vaisseaux lymphatiques of 
Decandolle, and the sap vessels of Grew and others, 
are all classed by Professor Lindley, under the denomi- 
nation of ducts ; which are scarcely allowed to be ves- 
sels, and yet they are vessels after all. Some are an- 
nular, some are reticulated, some are dotted, and some 
akin to spirals. We do not see that any particular ad- 
vantage results from regarding them in this light. A 
dotted duct is a doubtful spiral ; or it is a genuine 
spiral according to Kiesser, or, rather, it is a mere suc- 
cession of cylindrical cells, according to Professor 
Lindley. 
Duramen. — The several zones of wood, which are successively 
added to the trunk of exogenous plants, though at first 
colourless, acquire with age a deeper tinge, and are 
converted into what is called the duramen or heart- 
wood of the plant. The colour differs much in diffe- 
rent species. In the Oak it is of a deep brown ; in Gui- 
acum it is green, and in Ebony it is black. 
E or Ex.-— In the compostion of botanical terms, is merely 
the e or ex of the Latins, expressing negation, as e- 
ductulosce, without ducts, exstipulatee , without stipules. 
Elaboration. — Elaboration is the process by which aliment, 
after being absorbed or inhaled by the root or by the 
leaf, is depurated and prepared, by the proper organs 
for final assimilation. 
Elliptical. — Oval. When a leaf is twice as long as it is broad 
and nearly equally rounded at the extremity. 
Emarginate, — When there is nearly a triangular notch, in the 
summit of the leaf. 
Embracing Leaf. — A leaf, the base of which invests the stem 
or branch on which it grows, is in the language of 
botany, an embracing leaf. 
Endocarp. — The endocarp is the putamen or shell, immediately 
investing the seed or kernel of stone fruit. 
Endogenous. — Plants whose growth is affected by increments 
added to the centre, as in the case of the Palms, are 
said to be endogenous. They are all Monocotyledons. 
Endosmose. — A term introduced by M. Dutrochet, signifying 
a rush inwards, as applicable to the strong impulse by 
which a less dense fluid passes through animal or ve- 
getable membrane, to a more dense fluid, and hence, 
applicable to the impulse by which the moisture of the 
soil enters the spongiolae of the root. 
Ensiform. — Sword-shaped. When a leaf is long, tapering to 
a point, very thin on both edges, and slightly curved. 
Entire. — The margin of any part is so called when perfectly 
free from notches, or irregularities. 
Epicarp. — The epicarp is the external cuticle of stone fruit. 
Epidermis. — The epidermis, a term borrowedfrom the anatomy 
of animals, is the external envelope or integument of 
the plant, extending over its whole surface, and cover- 
ing the root, stem, branches, leaves, .flower, and fruit, 
with their appendages, excepting only the summit of 
the pistil, and surface of the spongiolae. But although 
it is thus extended over almost the whole surface of 
the plant, it is not of the same tenuity throughout. 
In the root and trunk, it is a tough and leathery mem- 
brane, or it is a crust of considerable thickness, while 
in the leaves, flowers, bud, scales and tender shoots, it 
is a fine, colourless, and transparent film, not thicker 
than a cobweb. It is colourless however, only when 
detached, for when adherent, it assumes the colour of 
the parts immediately beneath it. Hence the green 
colour so prevalent in the leaf and tender shoot, and 
the beautiful variety of hues, displayed in flowers and 
fruits. 
Epigynous. — Stamens that originate apparently in the ovary 
or pistil, as in the natural order of the Orchideae, are 
said to he epigynous. 
Epipetalous. — Stamens that originate apparently in the petals 
as in the genus Veronica, are said to be epipetalous. 
Ergot. — The most mysterious of all the maladies attacking the 
cereal grasses, is that of the Ergot or Spur. It is a 
firm, compact, and horn-like substance, white or grey 
within, and black, with a tinge of violet, without. It 
issues from between the glumes, and occupies the 
place of the grain ; or it is a prolongation of the grain, 
grooved and furrowed, and elongated to the extent of 
an inch. It is found most frequently on rye, but on 
almost all grains, particularly in barren soils. Mr. 
Francis Bauer seems to have regarded it, as being mere- 
ly a morbid swelling of the ear, not at all connected 
with the growth of a Fungus. Smith’s Introd. 348. 
But Decandolle, who has investigated the subject 
more recently, maintains that it is a parasitical Fun- 
gus, to which he gives the name of Sclerotium Clavus. 
Pays. Veg. iii. 1457- 
Erose. — Irregularly notched, having the appearance of being 
gnawed. 
Etiolation. — Plants are liable to a morbid or diseased affec- 
tion, originating in various causes, which entirely de- 
stroys their verdure, and renders them pale and sickly. 
This is called etiolation — the dtiolement of French 
writers, and may arise merely from the want of agency 
of light, or of the due evolution of oxygen, as may be 
seen in the case of plants placed in dark rooms, or 
between great masses of stone, or in the clefts of 
rocks, or under the shade of large trees. It may also 
c 
