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Darwin, Charles, 1809-1882

"Effects of Cross and Self Fertilisation in the Vegetable Kingdom"

In France M. Fermond more than once planted close together
varieties which ordinarily come true and which bear differently coloured
flowers and seeds; and the offspring thus raised varied so greatly that
there could hardly be a doubt that they had intercrossed. (5/7.
'F?condation chez les V?g?taux' 1859 pages 34-40. He adds that M.
Villiers has described a spontaneous hybrid, which he calls Phaseolus
coccineus hybridus, in the 'Annales de la Soc. R. de Horticulture' June
1844.) On the other hand, Professor H. Hoffman does not believe in the
natural crossing of the varieties; for although seedlings raised from
two varieties growing close together produced plants which yielded seeds
of a mixed character, he found that this likewise occurred with plants
separated by a space of from 40 to 150 paces from any other variety; he
therefore attributes the mixed character of the seed to spontaneous
variability. (5/8. 'Bestimmung des Werthes von Species und Varietat'
1869 pages 47-72.) But the above distance would be very far from
sufficient to prevent intercrossing: cabbages have been known to cross
at several times this distance; and the careful Gartner gives many
instances of plants growing at from 600 to 800 yards apart fertilising
one another. (5/9. 'Kenntnis der Befruchtung' 1844 pages 573, 577.)
Professor Hoffman even maintains that the flowers of the kidney-bean are
specially adapted for self-fertilisation.


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