PLANT ORGANS AND ORGANISMS 
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layer. When the mesocarp is fleshy, as in the Peach, it is called the 
sarcocarp. 
When the endocarp within the sarcocarp is hard, forming a shell or 
stone, this is termed a putamen. 
Sutures.- — The ventral suture is a line formed by the coherent 
edges of a carpellary leaf. The dorsal suture is the mid-rib of the 
carpel. Parietal sutures are lines or furrows frequently visible on the 
walls of fruits, formed by the ripening of a compound ovary. They 
occur between its dorsal sutures and indicate the places of union 
between adjacent septa or of two parietal placentas. 
Valves. — These are the parts into which the mature fruit separates 
to permit the escape of the seeds. Depending upon the number of 
these the fruit is said to be univalved, bivalved, trivalved, etc. 
Dehiscence.- This is the opening of the pericarp to allow the 
seeds to escape. 
Fruits are either Dehiscent or Indehiscent according as they open to 
discharge their seeds spontaneously when ripe (dehiscent), or decay, 
thus freeing the seeds, or retain their seeds, the embryo piercing 
the pericarp in germination {indehiscent) . Dehiscent fruits open reg- 
ularly, or normally, when the pericarp splits vertically through the 
whole or a part of its length, along sutures or lines of coalescence of 
contiguous carpels. Legumes usually dehisce by both sutures. 
Irregular or abnormal dehiscence has no reference to normal sutures, 
as where it is transverse or circumscissile, extending around the cap- 
sule either entirely or forming a hinged lid, as in Hyoscyamus, or 
detached. 
Dehiscence is called porous or apical when the seeds escape through 
pores at the apex, as in the Poppy; valvular, when valve-like orifices 
form in the wall of the capsule. Valvular dehiscence is septicidal, 
when the constituent carpels of a pericarp become disjoined, and 
then open along their ventral suture. Example: Colchicum; loculi- 
cidal, dehiscence into loculi, or cells, in which each component carpel 
splits down its dorsal suture, and the dissepiments remain intact. 
Example: Cardamon; septifragal dehiscence , a breaking away of the 
valves from the septa or partitions. Example: Orchids. 
Classification of Fruits (according to structure).- — Simple fruits 
result from the ripening of a single pistil in a flower. 
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