CLASSIFICATION OF FRITTS. 
83 
epidermis of the leaf; s, sarcocarp^ the middle, 
representing the parenchyma of the leaf; en- 
docarjp^ equivalent to the upper epidermis of the 
leaf; sd represents the dorsal suture ; sv^iliQ 
ventral suture ; a seed. In the cherry and 
plum, the sarcocarp is the part of the fruit 
which is eaten. In the almond the seed or pu- 
tamen is used as fruit, while its leathery covering, 
or sarcocarp, and the hard epicarp, are reject- 
ed. The pulpy matter found in the grape and 
gooseberry is formed from the placenta, and is not the sarco- 
carp. 
h. The external pieces^ which form the sides of the seed- 
vessels, are called valves. If a pericarp is formed of but one 
valve, it is univalved ; the chestnut is of this kind. A pericarp 
with two valves is said to be Mvalved^ as a pea-pod. The peri- 
carp of the violet is trivalved / that of the stramonium quadri- 
valved. Most valves separate easily when the fruit is ripe ; this 
separation is known by the term dehiscence. Sutures^ or seams^ 
are lines which show the union of valves ; at these seams the 
valves separate in the mature stage of the plant : they are very 
distinct in the pea-pod, which has two sutures. Partitions^ or 
dissepiments^ are internal membranes which divide the pericarp 
into different cells : these are longitudinal when they extend 
from the base to the summit of the pericarp ; they are trans- 
verse when they extend from one side to the other. Column^ 
or columella^ is the axis of the fruit ; this is the central point 
of union of the partitions of seed-vessels ; it may be seen dis- 
tinctly in the core of an apple. Cells are divisions made by 
the dissepiments, and contain the seeds ; their number is seldom 
variable in the same genus of plants, and therefore serves as an 
important generic distinction. Receptacle of the fruit is that 
part of the pericarp to which the seed remains attached until its 
perfect maturity; this organ, by means of connecting fibers, 
conveys to the seed, for its nourishment, juices elaborated by 
the pericarp. Some plants are destitute of a pericarp, as in the 
labiate flowers, compound flowers, and grasses ; in these cases 
tbo seeds lie in the bottom of the calyx, which performs the 
ofiice of a pericarp. 
Classification of Fruits. 
88. " The most scientific and natural method of classing fruits," says Mirbel, 
" would be to distribute them according to the vascular structure of pericarps and 
Mjeds, employing as secondary characters only the succulence or dryness of tlie tissue, 
or tlie indeliiscence of pericarps. The student would then perceive that the fruits 
h. Valves — Sutures — Partitions or dissepiments — Column — Cells — Receptacle of the fruit — Pericarp 
<ioinetiraes want'rg. — 88 Remarks Irom AJirbel respecting the classificutioji of fruits. 
