SEEDS. . 15 



property of geiwiinating most speedily ; planters are well aware that 

 they must be sown almost immediately after they ate taken from 

 the bush. Oleaginous seeds are generally preserved with great dit-, 

 ficulty ; so also are those of rubiaceous plants, of the- laurels, myr- 

 tles, &c.* ' 



In practical agriculture there is always much advantage, and 

 additional security, in sowing the most recent seed, even of kinds 

 wbitjh are known to be the longest lived. It frequently happens, 

 even after a very short time, that a certain proportion of these seeds 

 die : they have, perhaps, not been gathered under circumstances 

 favorable to their complete preservation. It is, therefore, only when 

 he is compelled to do so, that the farmer trusts wheat to the ground 

 which has been gathered in former years ; and experience has 

 proved that in using such seed, it is necessary to increase very con- 

 siderably the quantity sown. 



The inactivity of the seed ceases so soon as it is brought into 

 contact with water and the air under the influence of a sufficient 

 temperature. Sown in moist jsarth, a seedtabsorbs water, and swells 

 considerably ; the pellicle which covers it becomes distended, and 

 ends by bursting ; the radicle and the plumule appear, and become 

 more and more distinct ; the root penetrates the ground ; the plu- 

 mule by and by grows into a stalk which gets greener and greener, 

 increases rapidly, and augments the number of its leaves, so that 

 the young plant acquires vigor every day. At a certain period, 

 flowers appear ; and these are succeeded by fruit, the final term of 

 which is the maturity of the seed. The phenomena of vegetation 

 then cease. The whole of the organs of annual plants now wither 

 and die ; the work of reproduction, of multiplication, is accomplished. 

 Thus begins and ends the existence of the plants which are the 

 usual subjects of our husbandry. 



With regard to biennial plants and trees, which possess more than 

 this ephemeral existence, things pass differently. The plant vege- 

 tates so long as the temperature of the atmosphere and moisture of 

 the soil are favorable to it : during the cold season the leaves fall, 

 and the growth is suspended ; but the plant revives anew on the 

 return of spring. Those vegetables, the stem of which is generally 

 ligneous, and whose roots penetrate deeply into the ground, have a 

 power of resisting cold, and brave the rigors of the winter. In 

 these latitudes, the renewal of the vegetation of trees in the spring 

 presents an obvious analogy to the process of germination : the evo- 

 lution of the buds represents this process very closely ; and the phe- 

 nomena at large, which we observe in annual plants, are for the 

 major part reproduced • — there is increase of size in the stem and 

 root, sprouting of leaves, inflorescence, ripening of fruits, production 

 of seeds, and then suspension of function. 



In the tropics, where the temperature is nearly uniform through- 

 out the year, vegetation goes on without interruption ; it only varies 

 in its vigor, and this is determined by the abundance or the paucity 



 DecandoUe, Physiology, page 622 



