90 MR. J. SCOTT ON THE FUNCTIONS AND STRUCTURE OF THE 
any support to the opinion which I have already alluded to, 7. e. 
the absolute sterility of the long-styled unions. This view seems 
to be entertained by Professor Treviranus, who states (Bot. Zeit. 
1863, p. 6) that he found a plant of the long-styled Primula Au- 
ricula growing near a short-styled form, yet not one of the nume- 
rous flowers of the former produced a seed-capsule. We now 
know the absolute necessity for insect-agency in the fertilization 
of the long-styled form; hence, as I think, the observation of 
Professor Treviranus simply permits the inference that no insects 
had visited the plant. As all my results, however, have been ob- 
tained from less or more modified varieties of the Primula Auri- 
cula, whereas the observation of Professor Treviranus may possi- 
bly refer to the normal form of the species, objections may thence 
be taken to my regarding the former as correctly indicating the 
possible results of the latter. In view of such an objection, I can 
only add, that I have never had an opportunity of performing à 
single experiment on either form of the normal P. Auricula; but 
I can aver, from the examination of native specimens in herbaria, 
that the long-styled form does produce capsules containing good 
seeds. 
As bearing upon this point, however, I may state that I never 
succeeded in getting a single good seed from homomorphic unions 
of the long-styled form of Primula denticulata*. I had also a 
few flowers sent of the short-styled form of this species, with 
which I fertilized a single umbel of the former ; but in this case 
also, though a few capsules swelled, every seed was abortive. I 
do not, however, wish to be understood as positively inculcating 
the absolute sterility of this form ; though, certainly, I can assign 
good reasons for so regarding cultivated plants under homomorphic 
treatment. Thus, in the Royal Botanic Gardens of Edinburgh 
there are at present a few dozens of plants of the P. denticulata, 
consisting exclusively of the long-styled form. Mr. M‘Nab in- 
forms me that a varying number of these have been cultivated in 
the Gardens for upwards of eighteen years, yet, though affording 
annually a profusion of flowers, he has never known them to pro- 
duce a single seed. This evidence is of course open to the objec- 
tion that sterility in this case (as in that previously noticed) may 
* This species presents the two forms ; their long salver-shaped corollas ex- 
hibiting very marked differences from the positional changes in the attachment 
ofthe anthers. These are accompanied with other differences : the pistil in the 
long-styled form is fully four times as long as that of the short-styled; the 
stigma is also twice as long, and rougher; the pollen-grains smaller, but of à 
similar triangular shape in both forms. 
