From John Scott [20 November – 2 December 1862]1
– – seed.— P. vulgaris elatior and veris—carefully protected from cross-impregnation.2 But I never succeeded—as not a few aver they have—in raising oxlips from cowslips or primroses. The explanation of these cases where trustworthy authorities, have raised these very distinct forms from one plant, is I believe found in mediate or immediate crosses with the seed-producing plants. As you remark further experiments are absolutely necessary to show that these forms may originate in an independent and ungraduated manner from vulgaris. The permanence and stability—so to speak—of these three forms when raised from seed—as the majority of the offspring, at least, always represent their immediate parent, seems to demonstrate well-established characteristics, and inconsistent with the laws governing the reproduction of variations in the Phanerogamic Class of plants. These laws, however appear to me—not a little capricious in their mode of action in the Vegetable Kingdom—different I believe from what has place in the Animal—and present great difficulties to me in fully accepting your captivating theory of the origin of species by Natural Selection. Time however, does not permit me here to specify these difficulties, there are other points for present consideration.
In regard to the substitution of female flowers for male in Zea, it may be necessary to specify particularly that in the case I have given these were truly products of the male panicle.3 As in the axils of the upper leaves small monoecious spikes are occasionally produced, bearing a few male flowers at their base, and female on the upper part. I mention this now as you regard it as worthy of your recording; to prevent any equivocation to those who may have observed the latter spikes; and, therefore, in the case of a non-specific statement, suppose that those which are in reality female spikes, were taken advantage of.
I am extremely sorry that I can afford you no information whatever on the relative fertility of varieties of plants.4 I may mention, here, however, though you may already be aware of it an experiment which I made in illustration of the fertility of hybrids. This was made upon Clivia cyrtanthiflorum, which was raised by crossing the C. nobilis with C. miniata. I find it to be perfectly fertile with its own pollen as well as that of either parent.
I am in the same predicament in regard to your other question on the greater facilities certain species present for fertilisation by other pollen than their own. I have only one experiment I can give you on this point and it is quite inconclusive. I have more than one season fertilised flowers of Tacsonia pinnasistipula in the Gardens here,5 yet I have rarely succeeded in getting any fruit to set. During the latter part of this autumn another unnamed species flowered. I impregnated a flower of the former species—the only one upon the plant at the time—the ovary began to swell and promised fair for some time, eventually however it dropped off. But this I think was due to its being so late in the season, and the cold damp state of the atmosphere—the plant being grown in a cool greenhouse. I believe however if I had opportunities for experiment that it will present a very analogous case with Passiflora. In the course of the ensuing season I will commence a series of experiments on those interesting questions.6
And now before closing allow me to express my most sincere thanks for the honour you would have done in presenting me with a copy of your interesting work on Orchids, which I would indeed have highly valued.7 I have now, however, a copy of it in my possession, otherwise I would have gladly availed myself of your unmerited kindness to me in this likewise.
I remain | Sir | Your obedient Servt—
P.S. | Should you not be able to get a capsule of Vande〈ae〉 for comparison, I will have an Oncidium in flower, whic〈h〉 I will impregnate, and send along with Acropera.8 J. S.
JS does not fully accept natural selection.
Has never raised oxlips from cowslips or primroses; reports of such must be cases of crossing.
Discusses relative fertility of varieties, self-fertility of hybrids, and plans for experiments on enhanced hybrid fertility.
Please cite as
Darwin Correspondence Project, “Letter no. 3815,” accessed on 24 July 2016, http://www.darwinproject.ac.uk/DCP-LETT-3815