BOTANICAL SUBJECTS. 193 



(c.) Plants with verticillate leaves often have verticillate roots, as 

 Hippuris vulgaris and others. Asperida taurina* has four 

 leaves in a whorl, and curiously enoiigh, the creeping root- 

 stock is shown with four roots in a whorl, instead of leaves, 

 in its underground course. Galium palustre\ has four 

 leaves, and the underground part of the stem is shown 

 with four main roots at each node, instead of leaves, but 

 they are not so striking as in Asperula. 



18. It is interesting to study the germination of the lily seed, 

 as given by M. P. Duchartre.J At first the radicle lengthens. On 

 a part of it, which is not yet determinable, is afterwards formed the 

 first bud-scale. Afterwards the cotyledon releases itself from the 

 seed integuments, and raises itself above ground. Finally, on a 

 part of the radicle, already referred to, an enlargement apjDears, 

 which is the first scale of the bulb. Then, from the side of this, as 

 from an axilla, another scale arises, and from this a third, and so 

 on. The first radicle is transitory and disappears. Then below 

 the first bulb enlargement other roots bud out. These Duchartre 

 calls adventitious roots. Here we see that the caulicle is a part of 

 the radicle. It is known that it is a so-called caulicle at all because 

 the first scale is formed on it. When the so-called radicle dis- 

 appears, new so-called adventitious roots bud out of the base of the 

 scale. So that we have a leaf (scale) forming on the radicle, and 

 roots forming at the base of this leaf. The study of Duchartre's 

 observations lead one to conclude that the sub-division of the 

 germinating plant into radicle and caulicle is a botanical con- 

 ventionality, and much as if we took a round ruler, and drew a 

 line round its middle, and then determinined that one-half of the 

 ruler should be the caulicle and the other half the radicle ! 



19. It would appear that at the node, whether of a stem or 

 rhizome, or root, maybe developed either stipules or bud-scales, 

 leaves, or branches, and also roots. Sometimes all three are 

 developed, sometimes one or the other. When the nodes are on a 

 horizontal stem the roots and branches are opposed, when erect 

 the roots are likely to become whorled, as in grasses. 



20. In Nitella glomerata^ the verticillate roots are hardly 

 distinguishable from the branches. 



* " Syme's Brit. Bot.," vol. 4, p. 229. 

 t >. » » P- 221. 



JNotes et mem. " Jourl. Soc. Imp. et centr. d'Hort.," 2nd Sec. Tom. 8, 

 p. 554. 



§ "Syme's Brit. Bot.," vol. 12, p. 185. 



A p. 1724. Ij 



