152 
CLASSES OCTANDEIA AND ENNEAKTDRIA. 
with four pistils known in the class Heptandria ; its common 
name is lizard's-tail {Saururus). It has arrow-shaped leaves, 
flowers destitute of a corolla, and growing upon a spike ; it is to 
be found in stagnant waters. It gives name to the natural 
order Saurv/racecB j the flowers of which are achlamydeoits^ or 
without perianth. The number of stamens sometimes varies. 
204. Order Heptagynia^ seven pistils. — The Septas, a native 
of the Cape of Good Hope, is considered as the most perfect 
plant in this class, though its natural affinities are obscure ; it 
has seven stamens, seven pistils, seven petals, a calyx seven- 
parted, and seven ovaries (one to each pistil), which become 
seven capsules, or seed-vessels. 
205. Heptandria is the smallest of all the classes ; we do not 
find here, as in most of the artificial classes, any natural families 
of plants ; but the few genera which it contains differ not only 
in natural characters from other plants, but they seem to have 
no general points of resemblance among themselves. 
LECTURE XXYIII. 
OOTANDRIA, EIGHT STAMENS. ^ENNEANDRIA, NINE STAMENS. 
206. The eighth class, although not large, con- Fig. 139, 
tains some beautiful and useful plants. In the 
order Monogynia is the (Enothera^ or evening jprim- 
rose^ many species of which are common to our 
country ; some grow to the hight of five feet. The 
flowers are generally 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. 
a. This process of their opening is very curious ; the calyx sud- 
denly springs out and turns itself back quite to the stem, and the 
petals being thus released from the confinement in which they haa 
been held, immediately expand. There are few flowers which thus 
hail the setting sun, though many salute it at its rising. The 
flowers of the Oenothera are thickly clustered on a spike, and it is said tha 
*' each one, after expanding once, fades, and never again blossoms." Tliis flowt 
has been observed in dark nights to throw out a light resembling that of pho.i- 
phorus. The regularity of its parts renders it a good example of the eighth class, 
the different parts of its corolla preserve in their divisions tlie number four, or half 
the number of stamens. It has four large yellow petals ; the stigma is four-cleft ; 
capsule four-celled, four-valved ; the seeds are affixed to a four-sided receptacle. 
207. The CEnothera belongs to the natural order Onagra- 
203. naururus.— 204. Order Heptagynia.— 205. Remarks upon the class Heptandria. — 206. Bj^V^ 
iiaas — Evening primrose — a. Process of opening, &c. — 207. Natural o.tier, Onagracea. 
