526 



The Journal of Heredity 



strongly the tomato, but the eijidermis 

 is free of hairs like the nightshade. The 

 flowers are white with yellow middle 

 streaks. The fruit does not mature. 

 This particular type has appeared sev- 

 eral different times. 



"The form called Solanum proteus 

 also resembles the tomato more than 

 the. nightshade, although not to the 

 extent of leaf shape seen in 5. koelrenter- 

 ianiim. The stems and leaves are 

 hairy. The fruits produced arc smaller 

 than those of the tomato, but resemble 

 them in form."^ 



THE CHIMERAS EXPLAINED. 



Winkler's success now seemed com- 

 plete: he had produced four plants that 

 in appearance were genuine graft-hy- 

 brids in which the two parents were 

 wholly blended. The exact nature of 

 his success had not yet been explained, 

 however, and this explanation remained 

 for another German, Dr. Erwin Baur 

 of Berlin, who had been studying with 

 a microscope the cells in the leaves of 

 that very common perennial, the varie- 

 gated geranium {Pelargonium zonale). 

 Everyone knew that some geraniums 

 bear partly green leaves and partly 

 white ones, and that there are well- 

 fixed commercial varieties which regu- 

 larly bear green leaves with white 

 edges. Baur wanted to know why this 

 happened, so he began to raise sectorial 

 chimeras, made up of green geranium 

 and white geranium. It will be remem- 

 bered that, in favorable cases, these two 

 kinds of tissue exist side by side all the 

 way up the stem and in the terminal 

 bud. 



Now suppose that in this terminal 

 bud, where the two kinds of cells are 

 side by side, the white cells at the 

 surface begin to grow a bit faster than 

 the neighboring green cells, so that they 

 crowd over a little way into the green 

 territory. Then we have part of the 



» Stout, A. B. Plant Chimeras. Journal of N. Y. Botanical Garden, XIV, 164, pp. 145-150, 

 August, 1913. Winkler last year sent rooted specimens of these four chimeras to the New York 

 garden, where they have been propagated and distriliuted to several institutions in the United 

 States. In a letter dated Oct. 7, Dr. Stout says: "During the past summer, tlie chimeras have 

 done poorly, and flo not seem to rei)roduce readily through cuttings, altliough we have made 

 extra efforts to secure most favorable conditions for them. One of the chimeras, gaertnerianum, 

 has died out comjiletely. I find that tubingense and koelreuterianum are the only ones that 

 are inclined to make big, bushy plants. I saw Winkler's chimeras at Hamburg during the past 

 summer. None oi them were big, lusty i)lants. He propagates from terminal and sides branches, 

 getting young and rather small i)lants. I have secured the pure tomato and pure nightshade seeds 

 of chimeras and they grow very well." 



experiments. In 1908 he at last suc- 

 ceeded in producing what he wanted — 

 a graft-hybrid in which the union was 

 not a mere partnership between species 

 retaining each its own individuality, 

 but in which the two actually blended 

 into something new. After the number 

 of attempts had run up into the hun- 

 dreds, he finally observed a sprout 

 "which when propagated produced 

 plants having leaves, flowers and fruit 

 which were different from those either 

 of the tomato or of the nightshade. 

 This new form was named Solanum 

 tubingense. The general a]jpearancc of 

 this type is intermediate between the 

 tomato and the nightshade. The leaves 

 are simi^le, sharply serrate and often 

 lobed much like the leaflets of the 

 tomato plant. The stems and leaves 

 are hairy like the tomato. The corolla 

 and the calyx are larger than those of 

 the nightshade but smaller than those 

 of the tomato. The fruit is slightly 

 larger than the fruits of the nightshade, 

 which arc much smaller than the fruits 

 of the variety of the tomato used in the 

 graft. Many of the fruits of this type 

 are sterile but several generations of 

 seedlings grown from seed have been 

 pure nightshade and are not like the 

 plants Solanum tubingense from which 

 they were derived. 



"In continuing his experiments Dr. 

 Winkler soon obtained the three other 

 types of tomato-nightshade chimeras 

 shown in the plate illustrating this 

 article. Solanum gaertnerianum re- 

 sembles the nightshade more than the 

 tomato. The leaves are less entire than 

 those of the nightshade. The flowers 

 are greenish in color and are dwarfed, 

 the petals remaining rudimentary. This 

 form fruits sj^arsely but some seeds are 

 perfectly developed and produce pure 

 nightshade plants. 



"In general sha])e the leaves of the 

 form Solanum koelreuterianum resemble 



