GRAFT-HYBRIDS AND OTHER CHIMERAS 375 
first type is termed sectorial and the second periclinal. A third type 
has been recognized by Winkler in which the vegetative cone is a mosaic 
of unlike cells. This type he named hyperchimera. Coit has reported 
the case of a Valencia orange tree which from its consistent instability 
appears to have been propagated from a mixed bud and hence belongs in 
this class of chimeras. 
All of Winkler’s Solanum chimeras are periclinal and the degree of 
resemblance of such a graft-symbiont to the parent whose tissue comprises 
the inner portion of the shoot seems to depend upon the number of layers 
of cells from the other parent which envelop it. Thus the form tubigense 
Fig. 151.—Winkler’s Solanum chimeras. Produced by grafting tomato on nightshade 
(and vice versa). From left to right, Solanum Gaertnerianum, S. Koelreuterianum, 8S. 
proteus, and S. tubigense. The second resembles the tomato parent most closely; it has a 
tomato body with nightshade epidermis (a single layer of cells). The fourthis most like the 
nightshade parent and it has a nightshade body with tomato epidermis. The first has a 
tomato body covered with 2 layers of nightshade cells and the third, a nightshade body 
covered with two layers of tomato cells. Such combinations are called periclinal chimeras. 
(From Journal of Heredity.) 
(Fig. 151, D) which closely resembles the nightshade has all the inner 
portion of S. nigrwm, with just an epidermal layer, one cell thick, of S. 
lycopersicum. But proteus (Fig. 151, C), whose leaves are much more 
like tomato leaves, has a double layer of tomato cells overlying the 
nightshade body. Similarly, Kelreutercanum (Fig. 151, B) is really a 
tomato with nightshade epidermis, while Gertnerianwm has a tomato 
body covered with two layers of nightshade cells. These graft-hybrids 
were discovered only after much patient work in the course of which 
Winkler made 268 grafts which produced more than 3000 shoots. All 
four were propagated from cuttings and by this method they have been 
obtained and grown by the New York Botanical Garden. 
It has not been possible to compare these forms with true sexual 
hybrids because no one has yet succeeded in crossing the tomato and the 
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