100 MR. J. SCOTT ON THE FUNCTIONS AND STRUCTURE OF THE 
perimentations upon them with the pollen of the parental form 
(P. vulgaris), and likewise that of the other modified descendant 
(P. vulgaris, var. alba) resulted in the abortion of every seed! Such 
then are the experimental data from which the remarkable results 
stated in the latter part of Table V. were derived. That they are 
not sufficiently numerous to demonstrate the unconditional exist- 
ence of an absolute sterility between two modified descendants 
from a common parent, and also between the latter and one of 
the former, I have already admitted; nevertheless I think they 
clearly demonstrate the conditional existence of physiological 
divergences sufficient in extent to induce complete sterility. 
How, I ask, on any other grounds than by the admission of the 
conditional existence of such physiological divergences can we 
explain the phenomena in question,—namely, the existence of 
plants perfectly fertile when their flowers are fertilized by own 
pollen, and yet, at the same time, yielding naught but abortive 
results from those flowers fertilized by the pollen of the other 
variety and by that of their common parent ? 
I will now reduce, for the sake of comparison, the figures of the 
different unions given in Table V.; first of the long- and short- 
styled homomorphie unions, and second, of the long- and short- 
styled heteromorphic unions. 
Taste A.—Primula vulgaris and vars. alba and rubra. 
Lg S 3 
|o Ki z E 5 
E © "S © 
a ja ea 
Spior E terete 
uN LB Wa D 
331283 [35] 2 
383]88| H |86) B 
zi A Se |B a 
LonG-STYLED HOMOMORPHIC UNIONS. 
P. vulgaris, var. rubra, by own-form pollen... 100 | 78 | 1124| 100 | 1445 
P. vulgaris, var. alba, by own-form pollen ...| 100 | 50 | 560, 100 | 1120 
P. vulgaris, var. alba, by pollen of P.vulgaris 100 | 62 | 297, 100 | 480 
P. vulgaris by pollen of P. vulgaris, var. alba| 100 | 60 280 100 | 466 
SHORT-STYLED HOMOMORPHIO UNIONS. 
P. vulgaris, var. alba, by own-form pollen ...| 100 | 57 | 755, 100 1325 
P. vulgaris, var. alba, by pollen of P. vulgaris, 100 | 60 | 270 100 | 450 
P.vulgaris by pollen of P. vulgaris, var. alba.| 100 | 70 | 350 | 100 500 | 
