SPECIAL MORPHOLOGY: PHANEROGAMIA. 215 



points out to be insufficient, and that is all very well ; for instance, the 

 flat expansion, the bud in the axil, the respiratory function, and so on. 

 With the statement of that which leaves " ordinairement " are, nothing 

 at all is done ; in science we have precisely to insist on what is necessary 

 and constant. For the stem, in opposition to leaf and root, again, most 

 authors have no definition whatever ; or it is so fragmentary, that a very 

 moderate acquaintance with plants causes it to be cast aside, for instance : 

 The stem is the portion striving upwards, the axis of the plant (Kunth). 

 What, then, is the horizontally advancing rhizome of Asparagus, what 

 the flowering stem of Arachis hypogcea, nay, what even the twig of the 

 Weeping Ash ? (It is similar with Lindley, Link, and others.) Agardh 

 defines : The stem is that part of a vegetable from which the leaves ap- 

 pear to issue, and which appears to grow upward. That no scientific 

 definition can be built on mere appearances, every one will understand 

 who has not renounced all sound logic ; but what is the stem of Melo- 

 cactus, from which leaves neither issue nor appear to do so. But enough 

 of these examples. This much is clear, that we require, in science, 

 more definite and unchangeable characters, to keep apart the conceptions 

 which we wish to separate as actually different ; and, on the other hand, 

 such general characters that no member which belongs to the sphere of 

 the conception shall be excluded from it. By accurate and compre- 

 hensive investigations of nature, we are led to those distinct oppositions 

 of radicle and axis, of axis and leaf. The latter contrast is actually 

 manifested in nature ; whether it is to the purpose to attach chosen words 

 to it, is another question. The former contrast, as primary and ori- 

 ginal in the development, preeminently deserves an especial name, and 

 in this way every one knows certainly what he has to deal with, when 

 leaf, axis, radicle, &c., are spoken of ; and it is precisely on this that all 

 possibility of scientific intercommunication and progress depends. The 

 history of the formation of the embryo given above, which it may be ob- 

 served was known in its principal points long ago, nay, which is to be 

 found truly even in Malpighi*, refutes sufficiently all empty fictions as to 

 the origin of the axis from combined 

 leaf-stalks. Nature first displays 153 



a little undivided body (fig. 153. #), 

 which immediately elongating up- 

 wards becomes axis, and downwards 

 radicle. The forms which we have 

 named leaves (fig. 153. b, c) issue 

 out of this axis which pre-existed : 

 and that fiction is to the effect of 

 nothing less than to describe the 

 origin of an existing thing out of the 

 blending together of two things 

 which have no existence. Nay, to cut off all possibility of such flights 

 of fancy, Nature itself had formed the embryo of Cuscuta, in which, 

 although it attains a considerable length, no leaves whatever are usually 



* Anatome Plant., de Seminum Generatione, pi. xl. fig. 242. in Pisorum semine. 



153 HypocJuzris radicata. Development of the embryo, a, Youngest condition : the 

 embryo attached upon the suspensor, composed of three cells, is a little globule formed 

 of cells, b, Somewhat older germ : the dotted line indicates the original body, from 

 which the two first leaves (cotyledons) rise upward on each side of the apex (terminal 

 bud), which remains free, c, The same, but in a more advanced stage. 



p 4 



