216 VEGETABLE ORGANOGRAPHY. 



placed in favourable circumstances, can develope and 

 produce a new individual ; but we also know that this 

 development is more ready and vigorous, when we leave 

 around each the whole or part at least of the nourish- 

 ment which had been previously collected for it. Thus, 

 developments of this kind are favoured by the nourish- 

 ment accumulated in the tubercules, but may take place 

 by the forces peculiar to the germ which attracts the 

 surrounding water. There are, in fact, other tubercules 

 where we find the germ furnished with a very slight 

 provision of nourishment ; such are those which arise 

 from the roots of Saxifraya granulata, and the little 

 bulbs which are accidentally or constantly developed in 

 the axils of the leaves of several Liliaceas, and even in 

 the axils of their spathes, and which ma} r indifferently 

 be considered either as buds or tubercules. 



There are cases where the germs exist almost without 

 any provision, appearing under the form of dots, but 

 ready to be developed under favourable circumstances; 

 such are the points visible in the notches of the leaf of 

 Bryophyilum Calycinum, and which are developed 

 when this leaf, having become old, happens to touch the 

 moist earth. 



When the tubercules, which bear germs, become 

 detached from the plant which has given birth to them, 

 we can easily imagine that the double circumstance of 

 their being isolated bodies, closed on every part, and 

 capable of producing a new individual when sown, has 

 caused them to be taken for seeds ; this happens in 

 Ficaria, for example, where the development of these 

 bulbs has been described as a true germination. 



This error is the more excusable, as there are cases 

 where it is really difficult to elucidate the truth, and 

 where we observe remarkable affinities between seeds 

 and tubercules. 



