OEN 
pendicukr Iteiglit of one of them, and then 
doubling the product. 
OCTANDRIA, in botany, the eighth 
class in Linnfeus’s system, consisting of 
plants with hermaphrodite flowers, which 
are furnished with eight stamina or male or- 
gans of generation. There are four orders 
belonging to this class of plants which de- 
rive their names from the number of female 
organs possessed by the plants of each re- 
spective division. 
OCTANT, or Ocfile, in astronomy, that 
aspect of two planets, wherein they are dis- 
tant an eighth part of a circle, or 45° from 
each other.J 
OCTAVE, in music, an harmonical inter- 
val, consisting of seven degrees, or lesser in- 
tervals. See Music. 
OCTOBER, in chronology, the tenth 
month of the Julian year, consisting of thir- 
ty-one days : it obtained the name of Oc- 
tober from its being the eighth mouth in 
the calendar of Romulus. See the articles 
Month and Ykar. 
ODE, in poetry, a song, or a composi- 
tion proper to be sung. .Among the an- 
cients odes signified no more titan songs ; 
but with us they are very ditferent tilings. 
The ancient odes were generally composed 
ill honour of their gods, as many of those of 
Pindar and Horace. These had M-iginally 
but one stanza, or strophe, but afterwards 
they were divided into three parts, tlie 
strophe, the autistrophe, aud the epode. 
The priests going round the altar singing 
tlie praises of the gods, called the &-st en- 
trance, when they turned to the left, the 
strophe ; the second, turning to the right, 
they called antistrophe, or returning ; and, 
lastly, standing before the altar, they sung 
the remainder, which they called tlie 
epode. 
OECUMENICAL, signifies the same 
with general, or universal ; as oecuraetiifcal 
council, bishop, &c. 
OEDERA, in botany, a genus of the 
Syngeiiesia Polygamia Segregata class and 
order. Natural order of Composite Oppo- 
sitifoliiB. Corymbiferi®, Jussieu. Essential 
character : calyxes many flowered ; corrol- 
lets tubular, hermaphrodite with one or 
two female ligulate florets ; receptacle 
chaffy ; down of several chaffs. Tliere are 
two species, viz. O. prolifera, and O. aliena, 
both natives of the Cape of Good Hope. 
OENANTHE, in botany, dropwort, a 
genus of the Pcntandria Digynia class and 
order. Natural order of Umbellat®, or 
Umbelliferae. Essential character ; florets 
OES 
diSbrm ; in the disk sessile, barren ; fruit 
crowned with the calyx and pistil. There 
are eleven species ; of which O. crocata, 
hemlock water dropwort, commonly grows 
faiir or five feet high, with strong jointed 
stalks, which being broken emit a yellowish 
fetid juice ; the leaves are similar to those 
of hemlock, but of a lighter green colour ; 
the roots divide into four or five larger taper 
ones, having some resemblance to parsneps, 
for which they have been taken. It grows 
naturally in several parts of Europe, on the 
banks of ditches, rivers, and lakes. 
OENOTHERA, in botany, tree primrose, 
a genus of the Octandria Monosynia class 
and order. Natural order of Calycanthem®. 
Onagr®, Jussieu. Essential character: ca- 
lyx four-cleft; petals four; capsule cylin- 
drical, inferior ; seeds naked. There are 
eleven species ; of which O. biennis, broad- 
leaved tree primrose, has a fusiform, fibrous 
root ; from this, the first year, arise many 
obtuse leaves, spreading flat upon the 
ground ; from among these, the second year, 
come out the stems, three or four feet in 
height, upright, of a pale green colour ; 
flowers solitary, each being separated by a 
leaflet, or bracte ; they usually open be- 
tween six and seven o’clock in the evening ; 
for this reason the plant is called evening, 
or night primrose ; the mode of their ex- 
panding is ciu'ious ; the petals are held to- 
gether at top by the hooks at tlie end of 
the calyx ; the segments of which first sepa- 
rate at bottom, discovering the corolla, a 
long time Ircfore it acquires sufficient ex- 
pansive force to unhook the calyx at top ; 
when it has accomplished this, it expands 
almost instantaneously to a certain point, it 
then makes a stop, taking time to spread 
out quite flat ; it may be half an hour from 
the first bursting of the calyx at bottom to 
the final expansion of the corolla, which 
commonly becomes flaccid in the course of 
the next day, according to the Ireat or cool- 
ness of the weather ; the uppermost flowers 
appear first in June ; tlie stalks keep con- 
tinually advancing in height, and there is a 
constant succession of flowers till late in 
autumn. It is a native of North America. 
OESOPHAGUS, the gula, or gullet, is a 
membranaceous canal, reaching from the 
fauces to the stomach, and conveying into 
it tlie food taken in at the mouth. Its figure 
is somewhat like that of a funnel, and its 
upper part is called by anatomists the plia- 
rynx. See Anatomy. 
OESTRUS, in natural history, a 
genus of insects of the order Diptera. 
