340 REV. GEORGE HENSLOW ON THE 
(e) No benefit was derived from crossing with plants of a distinct stock. 1 
Besides this Hero, which appeared in the sixth [aj rbi and which, as stated, beat 1 
its opponent by about half per cent., two other “ heroes” appeared in the eighth gene- 1 
ration, the ratio of whose heights to those of their competitors were as 111:3 : 100, and 3 
as 140:5 : 100; but in other respects than height they do not appear to have been such 
fine plants as their opponents. Their offspring were not cultivated. 4 
The next remarkably self-fertile form to be noticed was a white or pale variety of. 
Mimulus luteus blotched with purple. This first appeared in the third generation, and. 1 
Mr. Darwin observes on it :—* From the tallness of this variety, the self-fertilised plants | 1 
exceeded the crossed plants in height in all the generations from the fifth to the seventh | 
inclusive." Moreover, this tall pale variety increased in the later self-fertilized gene- ` 4 
rations, owing to its great self-fertility, to the complete exclusion of the original kinds. 1 
The average ratio of the heights of this variety to that of the intercrossed was about. 
126 :100; and the ratio of fertility in the sixth generation was as 147: 100, i. e. the ] 
production of capsules; while the number of seeds of the former “ appeared decidedly - 
more numerous than those from the crossed plants." As with the descendants of Hero 1 
intercrossing with plants of the same stock did not benefit this variety. But when this 
highly self-fertile variety was crossed by a new stock, unlike Hero, it was vastly ben 
fited, as Mr. Darwin shows by the following results :— 
Weight of seed produced by the same number of ** Chelsea-crossed " and intererossed | 
plants, as 100 : 4. Weight of seed produced by the same number of Chelsea-erossed | 1 
and self-fertilized plants, as 100: 3. Weight of seeds produced by the same number of 
intercrossed and self-fertilized plants, as 100 : 73. 
Nicotiana tabacum is a third example; for the flowers on the parent plants, whid 
were self-fertilized by Mr. Darwin, “ yielded half again as many seeds as did those whiel 
were crossed ; and the seedlings raised from these self-fertilised seeds exceeded in heigh 
those raised from the crossed seeds to an extraordinary degree." 
Reseda odorata and R. lutea. Some plants of these two species are incompara : 
more self-fertile than other individuals. 
Pisum sativum. | ** The cultivated varieties of the common Pea are highly selí-fertile 
although they have been self-fertilised for many generations; and they exceeded i 
height seedlings from a cross between two plants belonging to the same co in th 
ratio of 115 : 100." Four pairs only, however, were compared. Let 
_ Primula veris. Of this species Mr. Darwin observes, “ The self-fertility increase 
dus several generations of illegitimate fertilization, which is a process closely analogou 
to self-fertilization, but only as long as the plants were cultivated under the same favou 
able conditions." He adds, 
** I have also elsewhere * shown that with Primula veris and sinensis, equal-styled varieties E 
appear which possess the sexual organs of the two forms combined in the same flower. Consequentl 
they fertilise themselves in a legitimate manner and are highly self-fertile ; but the remarkable factis | 
that they arerather more fertile than ordinary plants of the same species legitimately fertilised by] len. 
from a distinct individual." uc 
* Best d Dun. Soc., Bot. x. 1867, pp. 417-419. - 
