Igtt] CURRENT LITERATURE : 147 
NOTES FOR STUDENTS 
Graft hybrids and chimeras.—The large amount of recent work on graft 
hybrids, which has resulted in such astonishing discoveries as to their exact 
nature, seems to call for a collective review. In 1825 M. Apa, a French horti- 
culturist, by grafting Cytisus purpureus (a small tufted species) on Laburnum 
vulgare (an arborescent species) was much surprised to find that there 
resulted a shoot with somewhat intermediate characters. While the original 
individual has long been dead, the new form has been propagated by grafting 
and is somewhat common in cultivation; to it there has been given the name 
Laburnum Adami, and generally it has been regarded as a graft hybrid. Scarcely 
second in reputation to this, the most famous of the ‘graft hybrids,” is Craiae- 
gomes pilus, which is supposed to be a graft hybrid between Crataegus monogyna 
and Mespilus germanica; in this case the original tree is said still to exist in 
Lorraine. A third supposed case of a graft hybrid is the Bizzaria orange, 
which is thought to have arisen through the intergrafting of Citrus Aurantium 
and C. medica. While much study has been made of these peculiar plant 
forms, it is only very recently that their nature has been understood. 
grafted on S. Lycopersicum, and after growth had been resumed, a transverse 
cut was made in such a way as to sever both stock and scion, it being ho 
that adventive shoots would grow from the cut surface along the line of contact 
of stock and scion. Such adventive shoots actually appeared, and in one 
case the new shoot involved tissues of both stock and scion. However, the 
new form was not a graft hybrid, for clearly one side of the shoot was Solanum 
nigrum and the other S. Lycopersicum; to this peculiar structure WINKLER 
gave the suggestive name chimera. So sharply marked was the line between 
the tomato and the nightshade that some leaves were partly of one species 
and partly of the other. WxNKLER’s method soon yielded the results he had 
been seeking, for in 1908 he announced the production of a true graft hybrid,‘ 
a notable result, since never before had this been done under exact experimental 
control. To the new form there was given the name Solanum tubingense, in 
honor of the university town where the plant was produced. Out of 268 grafts 
between the tomato and the nightshade, there arose over 3000 adventitious 
shoots, among which there were five chimeras and the supposed graft hybrid 
Solanum tubingense; the latter, while intermediate in character, is somewhat 
closer to the nightshade than to the tomato. Early in 1909 WINKLER reported 
WINKLER, Hans, Ueber ie ae und pflanzliche Chimiren. Ber. 
pe Bot. Gesell. 25:568-576. figs. see Bot. GAZETTE 47:84. I 
Solan pene ag ein ee ter Salone er Tomate ‘oud 
Nedaehadie Ber. "De utsch. . Gesell. 264: 595-608. figs. 2. 1908; see Bor. 
GazETTE 47:250. 1909. 
