CLASS HEPTANDEIA. 
no proper corolla ; the six stamens and three pistils are S -ir- 
roiinded by six sepals, united at the base ; the stipules are of that 
peculiar kind called ochrea, or boot-like, forming sheaths around 
the stem above the bases of the leaves. The ColGhicum autum- 
nale is allied by many natural characters to the Crocus and 
Iris. The bulb is a subterranean egg-shaped stem, vidth the 
flower, like the Crocus, half hidden in the earth ; the bulb pos- 
sesses powerful medicinal qualities. In spring several narrow 
leaves arise, but the flower does not appear till September; 
the phyton lies buried in the root all winter, and is raised in 
spring to perfect its seeds before the next season. The flowers 
are pale purple : this plant is a native of England. 
CLASS yn. HEPTANDRIA, SEVEN STAMENS. 
202. Order Monogynia^ one pistil. — 'A fine specimen of this 
class and order is the chick- wintergreen {Trientalis) ; the calyx 
has seven sepals, the corolla is seven-parted. One species is said 
to defend its stamens against injury from rain, by closing its 
petals and hanging down its head in wet weather. There is 
sometimes to be found in this genus a variation in the number 
of stamens ; in which case the other parts of the flower also 
vary. This genus belongs to the great natural order, Prirrm 
lacecB. The cultivated Horse-chestnut 
JEsoulus (Fig. 138) is a native of the 
northern part of Asia, and was intro- 
duced into Europe about the year 1500 ; 
it was not probably brought to America 
until some time after the settlement of 
this country by Europeans. It is a 
small tree which produces white flow- 
ers, variegated with red, crowded to- 
gether in the form of a panicle; the 
whole resembling a pyramid. The blossom is very irregular in 
its parts ; that is, its other divisions do not correspond with the 
usual number of stamens ; the stamens, however, do not vary 
as to number. The seeds have a resemblance to chestnuts, but 
their taste is bitter. There are several native species of this 
plant in the Southern and Western States. The horse-chestnut 
exhibits in its buds the woolly envelope which surrounds the 
young flowers, the scales which inclose this envelope, and the 
varnish covering the whole. The stems and branches afford 
good subjects for studying the formation and growth of woody, 
or exogenous stems. The Horse-chestnut is the type of the 
natural order HippocastanecB. 
203. Order Tetragynia^ four pistils. — ^There is but one plant 
Colchicana.— 202. What plant is in the first order of ths seventh class 1— Horse-chestaiut. 
