THE FUNDAMENTAL TISSUE. 
121 
(a) The whole course of my description of tissue-systems necessitates the in- 
troduction of the idea of a Fundamental Tissue. It has, in fact, long been required ; 
it was often necessary, in anatomical descriptions of tissues which are neither epi- 
dermal nor fibro-vascular, to distinguish them by some common term. Many writers 
employ the term Parenchyma in this sense, in opposition to the fibro-vascular bundles 
and the epidermis; but this usage is not scientific; the fibro-vascular bundles often 
contain parenchyma, and, vice versa, the fundamental tissue is not aUvays paren- 
chymatous but sometimes distinctly prosenchymatous. We have, moreover, to deal 
here not with forms of cells, but with the contrast of different systems of tissue, 
each of which may contain the most various cell-forms. I must compare some- 
what more closely my description and use of terms wdth those of Nägeli. It 
might be supposed that Nägeli's Protenchyma is synonymous with my fundamental 
tissue ; but this is not the case ; the protenchyma of Nägeli is a much more 
comprehensive idea; everything which I call fundamental tissue is protenchyma, 
but all protenchyma is not fundamental tissue. Nägeli ^ says, for example, that he 
would call the primary meristem and all tissues which arise immediately from it 
(/. e. only through the medium of secondary meristem, but not of cambium) Prot- 
enchyma (or Proten) ; the cambium, on the other hand, and everything which 
directly or indirectly originates from it, Epenchyma (or Epen). When Nägeli gave 
these definitions, he was treating of fibro-vascular bundles ; and it is intelligible that 
he on this occasion included everything which does not belong to the fibro-vascular 
bundles under one common name (Proten). But our business is to give a uniform 
description of the various differentiations of plant-tissues; and there is no reason 
for bringing only into prominence the contrast between fibro-vascular and non- 
fibro-vascular tissues (Epenchyma and Protenchyma), and for considering all other 
differentiations as less important ; the protenchyma of Nägeli therefore includes, accord- 
ing to my use of terms, three kinds of tissue each of equal value with his epenchyma. 
The primary meristem is not more opposed to the fibro-vascular (epenchyma) than 
to the epidermal and fundamental tissues ; for the three systems of tissue equally 
arise by differentiation from it. The term Proten, after distinguishing from it the 
primary meristem, might be applied collectively to the epidermal and fundamental 
tissues ; but I see no reason for bringing into prominence this contrast alone ; the 
differentiation between epidermal and fundamental tissues is as essential as that between 
fibro-vascular bundles and fundamental tissue. From all this it follows that epidermal 
tissue, fibro-vascular bundles, and fundamental tissue are conceptions of equal value ; 
in each we find the most various forms of cells ; and secondary meristem may also 
arise in each. In the fibro-vascular bundles the cambium is of this nature; the whole 
of the young epidermis is a generating tissue in as accurate a sense as the cambium ; 
if this latter forms vessels, xylem, phloem, &c., the former produces hairs, stomata, 
prickles, &c. ; the phellogen, belonging to the epidermal system, arises still more de- 
cidedly as a generating tissue ; finally, even in the fundamental tissue a portion may 
persist for a considerable time as generating tissue, or may subsequently produce such 
a tissue, e.g. the meristem of the stems of Draccena, which brings about its increase 
in thickness, and thus forms new fibro-vascular bundles 
(b) Examples. The relationship of the three systems of tissue may be observed 
very readily, and undisturbed by subsequent formations, in the foliage-leaves of Ferns 
and of most Phanerogams; in these the fundamental tissue is generally the prevailing 
system, and is developed into different cell-forms. Isolated fibro-vascular bundles, 
separated by the fundamental tissue, traverse the petiole, and are distributed through the 
^ Beiträge zur wissenschaftlichen Botanik, Heft i, p. 4. 
^ Since the publication of the ist edition of this work, the classification of tissues here proposed 
has been generally adopted, especially by younger botanists ; as also in the main, with some 
deviations in particular points, by Russow, Unters, über die Leitbündelkryptogamen, Petersburg 1872. 
