CLASSIFICATION OF FRUITS. 115 



The pericarp consists of different parts, as, 



1st. Valves or external pieces, which form the sides of the 

 seed vessels. If a pericarp is formed of but one piece it is uni- 

 valved; the chesnut is of this kind. A pericarp with two 

 valves is said to be bivalved, as a pea-pod. The pericarp of 

 the violet is trivalved, that of the stramonium quadrivalved. 

 Most valves separate easily when the fruit is ripe ; this separa- 

 tion is known by the term dehiscence. 



2d. Sutures or seams, are lines which show the union of 

 valves ; at their seams the valves separate in the mature stage 

 of the plant ; they are very distinct in the pod which has two. 



3d. 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 ; 

 th6y are transverse when they extend from one side to the 

 other. 



4th. Column or columella, the axis of the fruit ; this is the 

 central point of union of the partitions of the seed vessels ; it 

 may be seen distinctly in the core of an apple. This was no- 

 ticed under the head of receptacles ; it is the receptacle of the 

 fruit. 



5th. Cells, are divisions made by the dissepiments, and con- 

 tain the seeds ; their number is seldom variable in the same 

 genus of plants, and therefore serves as an important generic 

 distinction. 



6th. Receptacle, is that part of the pericarp to which the 

 seed remains attached until its perfect maturity ; this organ, 

 by means of connecting fibres, conveys to the seed for its nour- 

 ishment juices elaborated by the pericarp. 



Some plants are destitute of a pericarp, as in the labiate 

 flowers, the compound flowers, and the grasses ; in these cases 

 the seeds lie in the bottom of the calyx, which performs the of- 

 fice of a pericarp. 



MirbeVs classification of Fruits or Pericarps. 



Mirbel has divided the fruits of all phenogamous plants into 

 two classes ; 1st. gymnocarps, which include all such as are 

 not masked or covered by any strange organ, or form no union 

 which conceals their true character. 2nd. angiocarps, which 

 include all fruits covered by any strange organ, which dis- 

 guises them from observation. 



Valves Sutures Partitions, or dissepiments Column Cells Receptacle 

 of the pericarp Pericarp sometimes wanting Mirbel's two grand divisions of 

 fruit. 



