296 MORPHOLOGY. 



within cells and absorption of the parent-cells. In very young tubers this 

 process of development goes on in a zone outside the vascular bundles ; 

 at a later period it enters into many situations throughout the whole 

 tuber in vertical rays in the pith, in horizontal ones in the rind. In all 

 the young pseudo-tubers all the cells exhibit most beautifully a circu- 

 lation branching out in reticulated currents from the cytoblasts, and 

 running with the greatest rapidity. 



All these forms here sketched have this in common, that they are 

 tubercular thickenings of a portion of an internode, at most of a whole 

 one (in the Dahlia), this alteration not contemporaneously affecting 

 the foliaceous organs or buds ; by this they all fall within a common 

 definition, and are at the same time clearly distinguished from the true 

 tubers, which always comprehend an entire axillary bud, i. e., all the in- 

 ternodes of an entire axis with its foliaceous organs and buds. The 

 so-called bulbs of Crocus belong here : they are nothing but the fleshily- 

 thickened bases of the axis of the bud. 



In the great abundance of so-called tubercular plants, it is very possible 

 that other and quite different forms of peculiar modifications of buds 

 occur ; on account of the great dearth of our knowledge of their develop- 

 ment nothing more can be said about them nay, the examples of the 

 forms noticed cannot be increased. A time must first come when the now 

 usually so dry and spiritless systematic works will give something more 

 than Planta tuberibus perennans or Radix tuberosa, &c. Such inves- 

 tigations are in the power of every one who has a tolerably good simple 

 microscope, which may be bought for a very little money ; and they 

 would further science more than the description of one hundred new 

 species in the superficial way just adverted to, from which one in fact 

 learns nothing more than that they exist upon the earth. 



Seed-buds (ovules, gemmuld). The last terminal and axillary buds 

 in the interior of the blossom assume a wholly peculiar form, of 

 which, however, I cannot speak until I come to the examination 

 of the apparatus for propagation. 



E. THE FLOWERS. 



137. We include both: a, every single organ of propagation by 

 itself, wherever unconnected with others on the same axis, through 

 a circle (or compressed spiral) of modified foliar organs (floral 

 envelopes), and b, every combination of several organs of propaga- 

 tion, collected within one floral envelope, and separated by this 

 from others, under the name of flower (flos) ; on the other hand 

 every collection of single flowers is an inflorescence (inflorescentia). 



If we review the whole kingdom of Phanerogamous plants, and seek in 

 the multiplicity of forms for a guiding clue, our impressions will lead us 

 to something like the following ideas : 



Two morphologically fundamental organs, axis and leaf, modified 

 toward this object in the preceding groups of plants; and two physiolo- 

 gically determinate organs, serving for reproduction, propagative cell, and 

 seed-bud (ovule), gradually developed ; the formative force of nature now 

 connects the propagative cell (pollen) with the leaf (anther), and the 

 seed-bud with the axis. We thus obtain two organs of reproduction at 



