| Comparison with 1861 | 
| 
 | 
| in the sterility of a multitude of species.  The evidence is, also, derived from hostile witnesses, who in all other cases consider fertility and sterility as safe criterions of specific distinction.  Gärtner kept during several years a dwarf kind of maize with yellow seeds, and a tall variety with red seeds, 
growing near each other in his garden; and although these plants have separated sexes, they never naturally crossed.  He then fertilised thirteen flowers of the one with the 
pollen of the other; but only a single head produced any seed, and this one head produced only five grains.  Manipulation in this 
 ease could not have been injurious, as the plants have separated sexes.  No one, I believe, has suspected that these varieties of maize are distinct species; and it is important to notice that the hybrid plants thus raised were themselves 
perfectly 
fertile; so that even Gärtner did not venture to consider the two varieties as specifically distinct.| ease 1861 |  | case 1859 1860 1866 1869 1872 | 
 | 
|  | 
| Girou de Buzareingues crossed three varieties of gourd, which like the maize has separated sexes, and he asserts that their mutual fertilisation is by so much the less easy as their differences are greater.  How far these experiments may be trusted, I know not; but the forms 
 experimented on| experimented 1861 1866 1869 1872 |  | experimentised 1859 1860 | 
are ranked by Sagaret, 
who mainly founds his classification by the test of infertility, as varieties.| on 1861 1866 1869 1872 |  | on, 1859 1860 | 
 | 
|  | 
| The following case is far more remarkable, and seems at first quite 
incredible; but it is the result of an astonishing number of experiments made during many years on nine species of Verbascum, by so good an observer and so hostile a 
 witness as Gärtner: namely, 
that yellow 
and white varieties of the same species of Verbascum when 
intercrossed 
produce less seed, 
than do either  
coloured varieties 
when fertilised with pollen from their own coloured flowers.  
Moreover, he asserts that 
when| witness 1861 1866 1869 1872 |  | witness, 1859 1860 | 
 | 
 
  
  
| in the sterility of a multitude of species.  The evidence is, also, derived from hostile witnesses, who in all other cases consider fertility and sterility as safe criterions of specific distinction.  Gärtner kept during several years a dwarf kind of maize with yellow seeds, and a tall variety with red 
 seeds, growing near each other in his garden; and although these plants have separated sexes, they never naturally crossed.  He then fertilised thirteen flowers of the one 
 with the| seeds, 1859 1860 1861 1866 |  | seeds 1869 1872 | 
pollen of the other; but only a single head produced any seed, and this one head produced only five grains.  Manipulation in this 
 case| with the 1859 1860 1861 1866 1869 |  | kind with 1872 | 
could not have been injurious, as the plants have separated sexes.  No one, I believe, has suspected that these varieties of maize are distinct species; and it is important to notice that the hybrid plants thus raised were themselves 
perfectly 
fertile; so that even Gärtner did not venture to consider the two varieties as specifically distinct.| case 1859 1860 1866 1869 1872 |  | ease 1861 | 
 | 
|  | 
| Girou de Buzareingues crossed three varieties of gourd, which like the maize has separated sexes, and he asserts that their mutual fertilisation is by so much the less easy as their differences are greater.  How far these experiments may be trusted, I know not; but the forms 
 experimentised on,| experimentised 1859 1860 |  | experimented 1861 1866 1869 1872 | 
are ranked by 
 Sagaret,| on, 1859 1860 |  | on 1861 1866 1869 1872 | 
who mainly founds his classification by the test of infertility, as 
 varieties.| Sagaret, 1859 1860 1861 |  | Sageret, 1866 1869 1872 | 
| varieties. 1859 1860 1861 |  | varieties, and Naudin has come to the same conclusion. 1866 1869 1872 | 
 | 
|  | 
| The following case is far more remarkable, and seems at first 
 quite incredible; but it is the result of an astonishing number of experiments made during many years on nine species of Verbascum, by so good an observer and so hostile a 
 witness,| quite 1859 1860 1861 1866 1869 |  | quite1872 | 
as Gärtner: 
 namely,| witness, 1859 1860 |  | witness 1861 1866 1869 1872 | 
that 
 yellow| namely, 1859 1860 1861 1866 1869 |  | namely 1872 | 
and white varieties 
 of the same species of Verbascum when| yellow 1859 1860 1861 1866 |  | the yellow 1869 1872 | 
intercrossed| of the same species of Verbascum when 1859 1860 1861 1866 |  | OMIT 1869 1872 | 
produce less 
 seed,| intercrossed 1859 1860 1861 1866 |  | when crossed 1869 1872 | 
than 
 do either| seed, 1859 1860 1861 1866 |  | seed 1869 1872 | 
coloured 
 varieties| do either 1859 1860 1861 |  | does either 1866 |  | the similarly 1869 1872 | 
when fertilised with pollen from their own coloured flowers.| varieties 1859 1860 1861 1869 1872 |  | variety 1866 | 
Moreover, he asserts 
 that| when fertilised with pollen from their own coloured flowers. 1859 1860 1861 |  | when fertilised with pollen from its own coloured flowers. 1866 |  | of the same species. 1869 1872 | 
when| that 1859 1860 1861 |  | that, 1866 1869 1872 | 
 |