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Show 182 DARWINIAN A. order those forms which varied upon the same stock, he ne~t had to combine similarly various forms which, though not found associated upon the same branch, were thoroughly blended by intermediate degrees: "The lower groups (varieties or races) being thus constituted, I have given the rank of species .to the. grou~s next above these which differ in other respects, 1. e., e1ther m characters hich were not found united upon certain individuals, or in ~ose which do not show transitions from one individual to another. For the oaks of regions sufficiently known, the species thus formed rest upon satisfactory bases, of which the proof can be furnished. It is quite otherwise with those wl1ich are r epresented in our herbaria by single or few specimens. These are p1·ovisional species-species which may.her.eafter fall ~o the rank of simple varieties. I have not been mchned.to preJudge such questions; indeed, in this regard, I am not d1spose~ to foll_ow those authors whose tendency is, as they say, to reumte spemes. I never reunite them without proof in each particular case; while the botanists to whom I refer do so on the ground of analogous variations or transitions occurring in the same genus or in the same family. For example resting on the fact that Quercus flex, Q. coccifera, Q. acutifol-ia, etc., have the leaves sometimes entire and sometimes toothed upon the same branch, or present transitions from one tr~e to another, !. mig~t 1·eadily have united my Q. Tlapuxahuensts to Q. Sa1·tortt of L1ebmann, since these two differ only in their entire or their toothed leaves. From the fact that the length ~f the peduncle varies in Q. Eobur and many other oaks, I might have combined Q. Seemcm~ii Liebm. with Q. salicifolia Nee. I have not admitted these mductions but have demanded visible proof in each particular case. Many species are thus left as provisional ; but, in proceedin()' thus the pro()'ress of the science will be more regular, and 0 ' 0 • 1 the synonymy less dependent upon tho caprice or the theoret10a opinions of each author." This is safe and to a certain degree judicious, no doubt, as respects published species. Once admitted, SPECIES AS TO VARIATION, ETC. 183 they may stand until they are put down by evidence d!rect or circumstantial. Doubtless a species ma; nght£ully be condemned on good circumstantial evidence. But what course does De Candolle pursue in the c~se-o£ .every-day occurrence to most working botamsts, haVIng to elaborate collections £rom countries not so well explored as Europe-when the forms in question, or one o£ the two, are as yet unnamed~ Does he introduce as a new species every form which · he cannot connect by ocular proof with a near relative £rom which it differs only in particulars which he see~ are inconstant in better known species of the same group~ We suppose not. But, i£ he does, little improvement for the future 11-pon the state o£ thinO's revealed in the following quotation can be expected~ "In the actual state of our knowledge, after having seen nearly all the original specimens, and in some species as many as two hundred representatives from different localities, I estimate that, out of the three hundred species of Cupulifer<E which will be enumerated in the Prodromus, two-thirds at least are provisional species. In general, when we consider what a multitude of species were described from a single specimen or from the forms of a single locality, of a single country, or 1 are badly described, it is difficult to believe that above one-third of the actual species in botanical works will remain unchanged." Such being the results of the want o£ adequate ~owledg~, how is it likely to be when our knowledge Is lar~ely mcreased ~ The judgment o£ so practised a bota~1st as De C~ndolle is important in this regaTd, and 1~ accords w1th that o£ other botanists o£ equal expenence. "They are mistaken," he pointedly asserts," who repeat that the greater part o.f our species are clearly |