(2

Conclusions 1865. Mitchella

Short-st. Eight pairs were fert. hetero-y─ & produced 7 berries: 9 berries gave average of 4.1 full-sized seeds ─ 9 pairs of fl. were fert. homo-y but produced not one berry; but last year of 2 prs of flowers thus treated one produced a berry with 2 seeds. Hence we see that the short-st. with own pollen are, like Primula, much more sterile than long-st, apparently in connection with liability of pollen falling on stigma.

Taking the 2 hetero-unions together 15/17 pairs of flowers produced berries & 19 berries gave an average of 4.4 seeds. Of the homo. unions 3/17 pairs of fl. produced berries & 6 berries gave average of 2.1 full-sized seeds. (a) maximum Thus the hetero. unions are in every way more than twice as fertile as the homo-unions.

When the long- & short-st. plants were kept under separate nets 3 plants of each form spontaneously yielded only 8 berries, containing an average of 1.5 full-sized seed; & there were a few berries which looked good but contained no seed. We thus see that both forms are very sterile when large insects are excluded tho' the fl. are frequented by thrips.

But Mr Scott tells me that one form at Edin. when unprotected produced plenty of berries, no doubt the fl. wd be visited for the copious nectar.