244 A. DeCandolle on the Life and Writings of Vaucher. 



point of rupture of the old ones. These plants are also re- 

 produced in two other ways : first, by natural slips (boutures), 

 as the greater part of aquatic plants ; and also in the manner 

 of the Utricularice, by their sterile stems. At the end of sum- 

 mer, indeed, we see the tops of these stems forming a dense 

 bud of undeveloped leaves, destitute of stipules and scales, 

 but copiously covered with a resinous varnish : now this bud, 

 which we should suppose destined to prolong the stem, on the 

 contrary becomes detached from it, and in spring-time deve- 

 lopes on one side leaves and on the other roots." 



In the Nymphceaceae the seeds germinate near the surface of 

 the water at the beginning of spring. 



The Melampyrum pratense, arvense and sylvaticum turn 

 their flowers towards the light, which is not the case with 

 Melampyrum cristatum. There is a similar observation on the 

 Narcissi, the flowers of which incline towards the light by a 

 double movement, that of the pedicel which bends, and that 

 of the peduncle which twists. During maturation the pedi- 

 cel and the capsule become erect, but the peduncle remains 

 twisted. 



" The most remarkable characteristic of the genus Alstroz- 

 meria is the tendency of the leaves to twist upon their petioles; 

 and what is singular in this is, that they have been predis- 

 posed for this arrangement, for, contrary to others, their upper 

 surface is dull and whitish, whilst the lower surface is shining 

 and of a fine green colour. This singularity, which pertains 

 in different degrees to all the Alstroemeria, is so independent 

 of temperature and of various atmospheric circumstances, that 

 these leaves, twisted at the base, do not unroll when they are 

 plunged into water." 



The capsule of Cerastium, at first ovoid, lengthens insen- 

 sibly, and finally becomes a tube more or less curved in the 

 form of a trumpet, and ordinarily divided into a number of 

 teeth double that of the styles. This singular conformation 

 serves in the first instance to protect the seeds, and afterwards 

 favours their dissemination instead of hindering it. The walls 

 of the curved tube are in fact so thin and so elastic, that on 

 the least agitation of the air, and sometimes even in the calmest 

 weather, the seeds may be seen to escape by sliding rapidly 

 along the tube, whose structure increases the movement. I 

 have often tried to follow them with a magnifying glass, but 

 they always escaped me by their extreme rapidity. We may 

 assert that they are projected by an unknown power. 



" The bulbs of Orchis are placed alternately right and left, 

 so that they cannot be truly said to advance always on the 

 same side, since, on the contrary, they constantly occupy the 



