[60]

[calculations]

Cotyledon of Red Cabbage Oct 8th

Diagram 3. Circumnutation from 10˚a.m to 8˚45' P.m on Oct 8th

(Circumnutation of which seedlings?)

(Reduced to 1/2 scale no lettering)

Fig 4 6 1/2 inch reduced to half

N.B. to [illeg] circumnutate of the hypocotyl & one cotyledon during 10 1/2 to 45m.

Figure here reduced to 1/2 origin scale

[61]

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Chapter 0 9

found more convenient to keep them separated. them. The present cases must not be confounded with those to be given in the next chapter in relation to of flowers which are sterile when insects are excluded; for such sterility depends not only merely on the flowers own pollen being impotent incapable of fertilisation with their own pollen, but on mechanical causes by which these pollen it is prevented from reaching the stigma, or by the pollen and stigma of the same flowers being mature at different periods.

In the seventeenth chapter of my Variation of Animals and Plants under Domestication I had occasion to enter on the present subject; and I will therefore give only a brief abstract of the cases there described, but others must be added, as why have an important bearing on the present work, Köhreuter long ago described plants of Verbascum phœniceum which during two years were sterile with their own pollen, but were easily fertilised by that of four other species; these plants however afterwards became more or less self-fertile in a strangely fluctuating manner; Mr Scott also found that this species as well as two of its varieties to be were self-sterile, as did Gärtner in the case of Verbascum negruw nigrum. So it was according to

[Cross and self fertilisation, pp. 329-30: "The cases here to be described might have been introduced in Table F, which gives the relative fertility of flowers fertilised with their own pollen, and with that from a distinct plant, but it has been found more convenient to keep them for separate discussion. The present cases must not be confounded with those to be given in the next chapter relatively to flowers which are sterile when insects are excluded; for such sterility depends not merely on the flowers being incapable of fertilisation with their own pollen, but on mechanical causes, by which their pollen is prevented from reaching the stigma, or on the pollen and stigma of the same flower being matured at different periods.
In the seventeenth chapter of my 'Variation of Animals and Plants under Domestication' I had occasion to enter fully on the present subject; and I will therefore here give only a brief abstract of the cases there described, but others must be added, as they have an important bearing on the present work. Kölreuter long ago described plants of Verbascum phoeniceum which during two years were sterile with their own pollen, but were easily fertilised by that of four other species; these plants however afterwards became more or less self-fertile in a strangely fluctuating manner. Mr. Scott also found that this species, as well as two of its varieties, were self-sterile, as did Gärtner in the case of Verbascum nigrum. So it was, according to this latter author, with two plants of Lobelia fulgens, though the pollen and ovules of both were in an efficient state in relation to other species."]