BENTHAM ON THE SPECIES AND GENEBA OF PLANTS. 145 



aparine ; that he has raised them in considerable quantities ; that he has 

 each year selected his seeds from such of his own seedlings as have 

 shown any tendency to variation ; and that this process has been carried 

 on in different soils, in different situations, in different climates, and at 

 different seasons. It is scarcely to be imagined that this has been done 

 for so very uninteresting a plant ; and yet, if any one of these precau- 

 tions has been neglected, it cannot be said to be proved that the plant 

 will never lose any of its characters. And, after all, what are these 

 characters, so invariably reproduced ? Not the want of hairs at the 

 nodes, nor the narrowness of the leaves, for these he admits to be varia- 

 ble in his G. tenerum — besides, that such hairiness is often scarcely per- 

 ceptible in the stoutest specimens of G. aparine — nor yet the gla- 

 brous or hispid fruit, for that is admitted to occur in both his species. 

 There remain, first, the size of the plant, not more than a foot in G. spu- 

 rium, often above three feet in G. aparine ; but to which would he re- 

 fer the numerous specimens occurring in some localities from 1 to 2 

 feet high ? 2ndly. The articulations, swollen in G. aparine, but not in 

 G. spurium, a mere result of the luxuriance of the former. 3dly. 

 The size of the fruit, 4 to 5 millimetres in G. aparine, 3 or 4 times 

 smaller, consequently 1 to 1J millimetres, in G. spurium. To verify 

 this character, I have measured the fruits of numerous specimens, living 

 and dried, of both forms, and I have never found the diameter quite so 

 little as 2 millimetres ; but from that size I have measured every inter- 

 mediate from half to half millimetres, up to 5 millim., the largest I have 

 met with. And 4thly. The hairs of the fruit, rising from a small tubercle 

 in G. aparine, and no such tubercles in G. spurium. As to this point, 

 if we take the hairy-fruited varieties of each form, I confess myself un- 

 able to discover any difference but what depends on size ; the larger the 

 fruit, and the larger the hairs, the more prominent are the tubercles at 

 the base. Upon the whole, as far as my own experience goes, the re- 

 sults of cultivation constitute an item, but one item only, and that often 

 a fallacious one, among the evidences on which the permanency of cha- 

 racter is to be judged by inductive reasoning. 



Even the proof of specific identity by cultivation is often liable to 

 error. Such experiments are often several years in carrying on ; it is 

 not to be expected that they can be daily watched during the whole of 

 that period, and all who have had the charge of gardens must be aware 

 of the mishaps which may occur during a short absence, without being 

 directly noticed — such as labels accidentally or intentionally destroyed 

 or misplaced, or the sown seed failing, or the seedling perishing, and re- 

 placed accidentally by some common allied species or variety. The ab- 

 normal circumstances in which a plant under cultivation is placed, may 

 also induce an apparent approach to some other species, without any 

 real alteration of essential character. I have already instanced the 

 Trifolium repens and hyhridum, as one in which the supposed proof of 

 identity by cultivation, notwithstanding my confidence in the experi- 

 menter, produces no conviction in my mind ; and it is only with great 



vol. i. — n. u. e, u 



