204 On the Chemical and Natural History of Lupuline. 



part of one of its two surfaces the mark of its point of 

 attachment, by which the grain has been originally attached 

 to the organ which produced it, which mark I usually de- 

 signate by the name of hilum. . . . When these grains 

 are examined, as recently obtained from the still living 

 female cone, they are found to be pyriform, with a peduncle 

 terminated by a hilum," &c. 



And farther on, § 387, pp. 176, 177, M. Easpail attempts ^ 

 to prove that the grains of lupuline emit pollen tubes, and 

 that these are produced in contact with' water. The con- 

 clusion of this paper will show the cause of the error of 

 this observer. 



Let us now study the origin of lupuline. 



It commences like a hair, by one cellule I (fig. 3, Plate 

 II.), which is developed between cells of the epidermis e. 

 This cellule, projecting to the exterior, is divided by a 

 transverse partition at the level of the external surface of 

 the epidermis. The utricle a, ovoid or elliptical, which 

 results from this division, is in its turn divided transversely 

 (fig. 4, a). The two new utricles enlarge ; the superior 

 a (fig. 5) is more dilated than the other, and is filled 

 with somewhat granular matter ; the inferior p forms a 

 short pedicel, which unites the former to the epidermis e, 

 by means of the primitive cell I. Thus far the multiplica- 

 tion goes on by transverse division ; it now proceeds verti- 

 cally. The terminal cellule a divides longitudinally into 

 two, as shown by figure 6 at a. Each of the two utricles 

 which thus originate produces in its turn, either one after 

 the other (figs. 7 and 9), or simultaneously (figs. 8 and 10), 

 two cellules, so that by this time the pedicel p is termi- 

 nated by three cells (fig. 7), or by four, as in figure 8. 

 The figures 11 and 12 show more advanced stages of this 

 subdivision. There now appear some new utricular ele- 

 ments in the interior of the terminal cells. Figure 13 

 presents a degree of multiplication still more advanced ; in 

 it may be clearly observed, m a a a a, the four terminal 

 cells of figure 8, and that they have divided in a radial 

 manner and parallel to the circumference. In figure 14, 

 which indicates a later phase, may also be observed the 

 four original divisions ; but the cells of each of these are 



