OF THE SEED AND GERMINATION. 



101 



as peaches, apples, melons, strawben-ies, goose- 

 berries, currants, &c., are applied. The pericarp 

 of the olive yields the purest and most esteemed 

 oil. Wine, so useful to man, when used' in 

 moderate quantity, is prepared of the juice ob- 

 tained by pressure from the fi-uits of the vine, 

 by submitting it to fermentation. Several other 

 fruits, such as apples, pears, rovifans, &c., afford 

 fermented liquors, which supply provinces and 

 entire nations with their ordinary drink. 



In the interior of several pericarps of the 

 family of Leguminosae, there is found an acidu- 

 lous or sweetish, but sometimes nauseating sub- 

 stance, which possesses laxative properties ; as is 

 observed in the cassia, the tamarind, the follicles 

 of the senna. Dates, figs, jujubes, and dried 

 raisins are alimentary substances which are re- 

 markable for the great quantity of saccharine 

 principle which they contain. The fruits of 

 tlie lemon and orange-trees contain citric acid 

 nearly in a pure state. The small berries of the 

 buckthorn {rliamnus catliarticus) are highly 

 purgative. 



Seeds are not less rich in nutritious principles 

 than pericarps. Those of the cereal plants or 

 graminese, and of many leguminosse, contain a 

 Itirge quantity of starch, which renders them 

 liighly nutritive. The seeds of the common 

 flax, the quince, and the psyllium, also contain 

 a very abundant mucilaginous principle, which 

 renders them essentially emollient. Many seeds 

 are distinguished by possessing a highly aromatic 

 stimulant principle. Such are those of the anise, 

 the fennel, the coriander, and the caraway, which 

 are named carminative seeds. Others, again, 

 produce a refrigerant or sedative effect upon the 

 animal economy; such as those of the calabash, the 

 cucumber, the melon, and the water-melon. The 

 carminative seeds all belong to the family of 

 umbellifersB ; the refrigerant to the cucurbita- 

 cese. The roasted seeds of the coffee and cocoa, 

 are used by all civilized nations. From the seeds 

 of the almond, walnut, beech, ricinus, hemp, 

 and poppy, an abundant oil is obtained, which 

 possesses properties modified in each of these 

 plants by its being mixed with other substances. 

 The seeds of Bixa orellana are used for dying 

 reddish brown. 



CHAP. XVII. 



OF THE SEED AND GERMINATION. 



We have seen that the fruit is essentially 

 composed of two parts, the pericarp and the 

 seed. 



The seed is that part of a perfect fruit \yhich 

 is found in the internal cavity of the pericai-p, 

 and wliich contains the body that is destined to 



reproduce a new individual. There are no naked 

 seeds, strictly so called: in other words, none 

 which are not covered by a pericarp. But this 

 latter organ is sometimes so thin, or adheres so 

 closely to the seed, that it cannot easily be dis- 

 tinguished at the period when the fruit is ripe, 

 on account of their being intimately attached to 

 each other, and confounded, although the two 

 parts were perfectly distinct in the ovary after 

 fecundation. Hence it is absolutely necessary 

 to examine the structure of the ovary with at- 

 tention, in order to understand the sti-ucture 

 which the fruit is to have. 



Thus in the grasses and synanthereae, the 

 pericarp is very thin and intimately adherent to 

 the seed, from which it is very difficult to dis- 

 tinguish it. This is equally the case in many 

 umbelliferae, and other plants ; whereas if we 

 examine them in the ovary, these two parts are 

 very distinct from each otiier. 



Every seed comes from a fecundated ovule. 

 Its essential character consists of its containing 

 an organized body, which, on being placed in 

 favourable circumstances, is developed and con- 

 verted into an individual perfectly similar to 

 that from which it derived its origin. This body 

 is the einbryo, which is therefore the essential 

 part of the seed. 



The seed is formed of two parts: \st, The 

 episperm, or proper integument ; Idli^, The ker- 

 nel contained within the episperm. 



The part of the seed by which it is 

 attached to the pericarp, is named the 

 umbilicus or Mlwin, represented fig. a, 

 in the common wheat. It is also 

 familiarly known as the eye of the com- 

 mon bean. The hilum is always mark- 

 §ed, on the proper integument, by a 

 kind of cicatrix or scar of greater or less 

 extent 5, which never occupies more than 

 , a part of its surface, and by means of 

 which the vessels of the trophosperm communi- 

 cate with those of the proper integument of the 

 seed. The centre of the hilum always repre- 

 sents the base of the seed. Its summit is indi- 

 cated by the point diametrically opposite to the 

 hilum. 



When a seed is compressed, the surface which 

 looks to the axis of the pericarp is the face, and 

 that which is directed towards the wall of the 

 pericarp is named the back. The margin or edge 

 of the seed is repi'esented by the meeting of the 

 face and back. 



When the hilum is situated on some part of 

 the edge of the seed, the latter is said to be com- 

 pressed. It is depressed, when the hilum is 

 placed on its face or back. 



Every seed connected by its extremity with 

 the bottom of the pericarp, or of one of its cells, 

 when it is multilocular, and following the same 

 direction in a more or less decided manner, is 



