GERMINATION. 97 



and uncovered ; the little leaves of which it is composed expand, 

 increase in size, become green, and begin to draw from the 

 atmosphere a portion of the fluids which nourish the young plant. 

 The act of germination is now at an end, and nutrition goes on 

 as we described it when speaking particularly of this function. 



47. All seeds do not require the same period of time for their 

 germination. For instance, certain cresses germinate in two 

 days ; the turnip and bean in three days ; lettuce in four ; the 

 melon in five ; most of the grasses in six or seven days ; the 

 hyssop in a month ; the peach in a year, and rose tree in two 

 years, &c. 



48. What we have hitherto said of fructification relates entirely 

 to cotyle'donous plants ; and we have still to say a few words of 

 what takes place in acoty'ledons (from the Greek, a, without, and 

 kotuledbn, seed-lobe), in which we find neither flowers, nor seed, 

 nor embryo. The class of acoty'ledons comprises all plants 

 which are unprovided with true organs of generation, that is, 

 stamens and pistils ; on this account they are named crypto' gam- 

 ous (from the Greek, kruptos, concealed, and gamos, marriage) 

 or agamous (from the Greek, a, without, and gamos, marriage), 

 and are produced through the means of corpuscules, analogous 

 in their structure and development to the bulbills or bulblets of 

 certain perennial plants. These corpuscules (minute bodies) are 

 named sporules or seminules ; they are contained in envelopes 

 called conceptades, and are variously placed either in the interior 

 of the plant itself, or (but more rarely) on its exterior in the form 

 of tubercles, as we shall see when we come to speak of the his- 

 tory of these plants. 



47. Do all seeds require the same time for germination ? 



48. What are acoty'ledons ? What plants are contained in the class of 

 acoty'ledons ? What are crypto'gamous plants ? 



