220 BOTANY FOR BEGINNERS CHAP. 



examples of albuminous seeds, -and Peas and Beans of exalbum- 

 inous seeds. In a few cases, reserve material is formed from 

 the nucellus (p. 201), which is around the embryo-sac, when 

 the tissue formed is called perisperm. Examples Henbane and 

 Piper. 



Results of Fertilisation. The fertilisation of the oosphere 

 has far-reaching results. These are shown below in a tabular 

 form. 



1. The oosphere is converted into an oospore, from which, by 

 development, the embryo is produced. 



2. The embryo-sac is filled with endosperm, which may be 

 used up by the developing embryo or stored up until the seed 

 germinates. 



3. The ovule is converted into a seed. 



4. The ovary is converted into a fruit. 



SUMMARY. 



Flowering Plants differ from non-flowering plants in the production 

 of seeds. 



Seeds are formed from ovules by the changes which go on after 

 fertilisation. 



Pollination is the distribution of the pollen from the anther to the 

 stigma, It can take place in two different ways (i) Cross-pollination, 

 when the pollen of A finds its way to the stigma of B ; (ii) Self-pollina- 

 tion, when the pollen of A finds its way to the stigma of A. 



Contrivances to Prevent Self-Pollination . These are (i) The flowers 

 may be diclinous (p. 208) ; (ii) the plants may be monoecious or 

 direcious (p. 208) ; (iii) the flowers may be protandrous or proto- 

 gynous (p. 209) ; (iv) the plant may produce two or three kinds of 

 flowers ; (v) the pollen of A may have no effect on the stigma of A. 



Insect-Pollinated flowers are (i) Brightly coloured, sweet scented, 

 and very prominent ; (ii) they produce either honey, or plenty of 

 pollen, or both ; (iii) their pollen is sticky ; (iv) their stigmas are 

 small. 



Dimorphic Plants produce two kinds of flowers ; these are (i) 

 Flowers with short-styles ; (ii) flowers with long-styles. 



The pollen of the short-styled form pollinates the stigma of the long- 

 styled form, and the pollen of the long-styled flower the stigma of the 

 short-styled form. 



Trimorphic Plants produce three kinds of flowers ; these have three 

 lengths of style. 



Humble-Bee F/oivers, such as the Clover, Vetch, and Pea, cannot be 

 pollinated by any other insect because their tongues are not long 

 enough. 



Wind-Pollinated Plants produce flowers which possess the following 

 characters (i) The flowers are small, and generally green ; (ii) the 



