CLASS OCTANDRIA. 
203 
of the southern and western states. The horse-chesnut exhib- 
its in its buds in a very conspicuous manner the wooly envelope 
which surrounds the young flowers, the scales which cover this 
envelope, and the varnish which covers the whole. The wood 
of this tree affords a good subject for studying the formation 
and growth of woody or exogenous stems. 
TETRAGYNIA. 
There is but one plant with four pistils known in the class 
Heplandria ; this alone constitutes the fourth order ; its com- 
mon name is lizard’s-tail, ( Suururus ,) it has arrow shaped 
leaves, flowers destitute of a corolla, and growing upon a spike ; 
it is to be found in stagnant waters. 
HEPTAGYNIA. 
The septas, a native of the cape of Good Hope, is considered 
as the most perfect plant in this class ; it has 7 stamens, 7 pis- 
tils, 7 petals, a calyx 7 parted, and 7 germs, (one to each pistil,) 
which germs become 7 capsules, or seed vessels. 
lleptandria is the smallest of all the classes ; we do not find 
here as in most of the other classes, any natural families of plants; 
but the few genera which it contains not only differ in natural 
characters from other plants, but seem to have no general points 
of resemblance among themselves. 
LECTURE XXVIII. 
CLASS VIII OCTANDRIA. CLASS IX ENNEAN'DRIA. 
Monogynia. 
The eighth class although not large contains some beautiful 
and useful plants. One of the first which we meet with in this 
class, is the scabish, ( Oenothera ,) sometimes called evening 
primrose. 'Many species of this are common to our country, 
some grow to the height of five feet. The flowers are general- 
ly of a pale yellow, and in some species they remain closed 
during the greater part of the day, and open as the sun is near 
setting. This process of their opening is very curious, the 
calyx suddenly springs out and turns itself back quite to the 
Tetragynia — Saururus — Order Hcptagynia — Septas smallest of the class 
— Class Octandria — Order Monogynia — Evening Primrose — 
