MORPHOLOGY OF ANGIOSPERMS. 145 



glands known as nectaries which are variously located; fre- 

 quently they are on the torus either between the ovary and sta- 

 mens (Fig. 83) or between the stamens and petals. Some- 

 times the stamen is modified to a nectar-secreting spur as in the 

 violets. In aconite the nectary is developed from one of the 

 posterior petals (Fig. 84, E). In seeking the nectar the pollen 

 of the ripe anther may fall upon or adhere to the insects and thus 

 be carried from one flower to another (Fig. 86). 



Honey is a product formed through transformation of the 

 plant nectar by honey bees. The nectar is supposed to be acted 

 upon by certain salivary secretions of the bee and changed into a 

 fruit-sugar, the so-called honey, consisting of a mixture of dex- 

 trose and levulose. The nectar of buckwheat and clover (partic- 

 ularly white clover) is the principal source of the commercial 

 article. The nectar of some plants is poisonous and may furnish 

 a poisonous honey (see p. 357). 



V. THE FRUIT. 



After the fertilization of the ovule or ovules, the parts of the 

 flower that play no further i)art either in protecting the seed or 

 aiding in its dispersal soon wither and arc cast ofl' : in most flowers 

 the petals lose their color and, together with the stamens, style 

 and stigma, wither and fall away shortly after fertilization. The 

 stigma ma\', hovvcver, persist, as in the poppy ; the style may like- 

 wise remain, as in Ranunculus, or even centinue to grow or 

 lengthen, as in Taraxacum: in other cases the calyx persists, as 

 in orange and belladonna ; in still other cases the torus may be- 

 come fleshy and form a part of the fruit, as in pimenta and apple. 

 The fruit may consist, therefore, not only of the ripened pistil, 

 but also of other parts of the flower and torus which persist or 

 develop witli it. 



The wall of the fruit is called the pericarp, and, like the leaf, 

 it consists of three distinct layers, viz. : ( i ) the outer layer corre- 

 sponding to the outer epidermis of the ovary is called the eimcari- 

 or exocarp : (2) the inner laver corresponding to the inner epi- 

 dermis of the ovary is called the exdocarp. or. from the fact 

 that it is sometimes hard and stone-like, it is called the puta- 



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