The Simple Fruits (page 4)

Dry indehiscent fruits retain their seeds and do not crack open after ripening. We will examine four different types.

C. Simple Dry Indehiscent Fruit

1. The Achene

The achene consists of a single seed that is attached to the wall of the ovary at only one point. The wall of the mature ovary is also thin and undeveloped so when it dries out the fruit formed has a seed-like appearance. Examples of achenes include sunflowers, dandelions and buckwheat. Don't be confused to learn that the sunflower "seed" is actually a fruit. Remove the dried up wall of the fruit and the sunflower seed is found underneath.

  2. The Grain

 If the wall of the dry indehiscent fruit is thin, transparent and firmly attached to all points of the seed coat the fruit is a grain. Grain type fruits are produced by members of the grass family which include important food crops such as rice, corn and wheat.

  3. The Samara

 

 
 The Samara is a wind borne fruit containing a single seed. It is much like an achene except for the paper-like wing which develops from the ovary wall of the flower. Winged Samara fruits are characteristic of elms, maples and ashes.

4. The Nut

 

 

 
Except for its larger size, the nut is very similar in structure to the achene. In nuts such as the acorn and chestnut the shell is the coat of the fruit. It, the coat, develops from the ovary wall after fertilization. Some nuts have a husk covering the hard shell. In this case the husk is formed from the outer layer of the ovary wall and the hard coat of the nut is formed from the inner layer of the ovary wall. Walnuts and pecans are examples of the later type of maturation.

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