The mutation theory; experiments and observations on the origin of species in the vegetable kingdom . elina tuberosa. Geranium pratense is only to be boughtin two forms, white and blue. I ob-tained seeds from two plants whichwere bought as Var. alba and raisedfrom them, besides pure wdiites,plants wnth all grades of color ar-rangement from striping and secto-rial variations to complete blue (Fig. 21). If it is thought desirable to putthe striped variety on the market itmust be purified by selection. Thestriping first appears as single finestreaks on occasional flowers. Ifthese plants are isola
The mutation theory; experiments and observations on the origin of species in the vegetable kingdom . elina tuberosa. Geranium pratense is only to be boughtin two forms, white and blue. I ob-tained seeds from two plants whichwere bought as Var. alba and raisedfrom them, besides pure wdiites,plants wnth all grades of color ar-rangement from striping and secto-rial variations to complete blue (Fig. 21). If it is thought desirable to putthe striped variety on the market itmust be purified by selection. Thestriping first appears as single finestreaks on occasional flowers. Ifthese plants are isolated and theirseeds sown separately the majorityof the plants raised are pure white,but occasional ones are produced with broader and more numerous stripes. The seeds ofthese are saved, and so on. The object is to isolate thestriped race from the white, and this can be attained inthe course of a few years. On the other hand the breederlias to fight against the tendency of the striped form toreturn to the full blue either by buds or through is to guard against this that Vilmorin recommends. Fig. 21. Geranium pra-tense album with pie-bald blue and white flowers,parts ofwere bluewhite. The dark the petals the others 120 Atavism. the selection of seeds from tlie palest examples of thestriped forms. Convohulus tricolor was the first species in whichthis mode of origin of the striped form was observed(1840). It was followed by Gomphrcna globosa, Antir-rhinum majiis album and liLtewn, Ncmophila insignis, Por-tiilacca grandiflora, and others. Of recent years a largenumber of blotched varieties have been obtained in vari-ous nurseries; and always, so far as is known, in thesame way, by so-called partial reversion of a white oryellow variety to the red or blue color of the parentspecies. In the following sections we will therefore examinein detail some cases of striped flowers as instances ofphysiological atavism. §14. ANTIRRHINUM MAJUS STRIATUM.(With Plate I.) Amongst the numer
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