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Botany 1050

Introduction to Botany

Spring 2008

 

FRUITS


I. Fruit = a mature, or ripened, ovary along with its contents and any adhering structures

A. Contrast with vegetable = a vegetative (non reproductive) part

II. Fruit development

A. While the seeds are developing the ovary wall (and sometimes other tissues) develops into the fruit wall (pericarp)

B. Pericarp = the fruit wall. There are three layers, but they are not always distinguishable:

1. Endocarp - inner layer

2. Mesocarp - middle layer

3. Exocarp - outer layer.

C. The type of fruit that forms will be determined by the insertion of the floral parts, placentation, ovary wall development and sometimes other tissues involved in its formation

III. Fruit classification

A. Number of pistils it is derived from:

1. True (simple) fruit - derived from a flower with one pistil

2. False (compound) fruit - derived from more than one pistil

B. Position of the ovary

1. Superior 

2. Inferior

C. Mature pericarp

1. Dry - pericarp remains thin and dry

2. Fleshy - pericarp (and sometimes accessory tissues) enlarge and become fleshy to attract seed dispersers

D. How the seeds are released (applies only to dry fruits)

1. Dehiscent - the pericarp splits open at predetermined point(s)

2. Indehiscent - the pericarp does not split open at predetermined point(s)

IV. A key to the common fruits is available here. You should print it out and bring to both lecture and lab.


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