APPENDIX IV 195 



toplasm of the plant to unite with the nitrogen of the nitrates and 

 with the sulphur and phosphorus of other mineral matters derived 

 from the soil, and a compound is formed called (26) which the grow- 

 ing regions use to make into more (27). This last change is called 

 assimilation. 



Some of the proteids may also be stored for future use. Food 

 may be stored in the (28), the (29), the (30), the (31), or in any thin- 

 walled cells. 



OPTIONAL. THE LIFE-HISTORY OF A SEED-PLANT 



See note, p. 193. 



The mother-plant produces flowers which attract insects by their 

 (1) or by their (2). These animals carry (3) on their hairy bodies 

 from the (4) of one flower to the (5) of another. Here nourished 

 by a (6) it sends out a tube which grows down through (a) the (7), 

 (6) the (8), and (c) the (9), and here enters a tiny opening called the 

 (10) in the (11). There a nucleus of the pollen grain (called a sperm 

 nucleus) unites with a nucleus of the egg-cell in the ovule during the 

 process of (12) to form one cell (called a fertilized egg-cell) which 

 now develops into a tiny plant known as the (13) of the seed. This 

 little plant has (a) a minute stem called the (14), (b) one, two, or 

 more seed-leaves known as (15), and (c) usually a tiny bud called the 

 (16). 



The mother-plant feeds this embryo until it has grown thus far, 

 and also stores up food for further growth. This may be put in the 

 cotyledons as in the (17) seed, or it may be packed around the 

 embryo, when it is called (18), as in the (19). To protect the embryo 

 until time for germination, the seed has one or more outer coverings 

 known as (20). That the seed may be carried away from the mother- 

 plant, and so have better opportunities for development, the 

 mother-plant provides the fruit or the seeds (a) with (21) or (22) so 

 they may be carried by the wind, or (b) with (23) so they may cling to 

 the wool of animals, or (c) with (24) so they may tempt animals to 

 eat them ; in the last case (as in the peach or cherry) the contents 

 of the seed are protected by (25). 



