1911] CURRENT LITERATURE St 
Laburnum Adami. If this plant is really a hybrid, owing its origin to a fusion 
of diploid nuclei of Laburnum vulgare and Cytisus purpureus, its nuclei should 
be tetraploid; but they were found to be only diploid, and STRASBURGER 
regarded this as evidence against the hybrid character of the graft. After 
NeEMEc'’s had reported vegetative fusions of nuclei followed by reduction 
phenomena in chloralized root tips, STRASBURGER repeated the experiments, 
but could not confirm NEMEc’s results, and therefore concluded that they had 
no significance so far as Laburnum Adami was concerned, and also that in the 
structure of their nuclei, plants known as graft hybrids show no indication of 
a hybrid character. 
At this stage in the development of the subject, WINKLER™ secured from 
Solanum Lycopersicum and S. nigrum plants which were acknowledged to be 
graft hybrids, and he asserted that they would necessitate a fundamental 
revision of our theories in regard to inheritance, and especially in regard to the 
rdle of the nucleus in heredity. Since the threatened theories were due to 
STRASBURGER more than to any other botanist, he felt called upon to defend 
them, and securing material by grafting Solanum Lycopersicum and S. nigrum, 
he examined the nuclei, but did not find them to be different from those of other 
graft hybrids which he had previously investigated. There was no migration 
of nuclei, no fusion of nuclei of scion and stock, or any regulative reduction 
processes. He would regard WINKLER’s graft hybrids as more or less com- 
plicated chimeras and would call them ‘“‘hyperchimeras.” 
In many angiosperm parasites (like mistletoe) the relation between parasite 
and host is very intimate, but there is no mingling of nuclei. In grafting, it 
seems possible that a bud from the point of union might give rise to a shoot 
bearing a flower in which an anther might be from the scion and an ovary 
might be from the stock. Close fertilization might then give rise to a true 
hybrid, but hyperchimeras, SrRASBURGER thinks, would be more likely to pro- 
duce flowers, the seeds of which would give rise to pure plants of either the 
scion or stock. | 
The fact that pollen from his graft hybrids would cause fertilization in 
Solanum nigrum or S. Lycopersicum, while neither of these plants can be crossed 
with the other, WINKLER regards as proof of hybrid character; but Srras- 
BURGER thinks that the pollen was probable pure, and consequently fertiliza- 
rion was to have been expected, but that only S. nigrum or S. Lycopersicum 
would result. 
STRASBURGER publishes no figures and refrains from giving a detailed 
account of nuclear phenomena, because WINKLER’S full paper has not yet 
heen published; but his examination satisfies him that WINKLER has produced 
5 NEME , Ueber die Entwickelung des Chloralhydrats auf die Kern- und 
Zellteilung. aa Wiss. Bot. 39:645-730. 1904 
6 WINKLER, Hans, Weitere Untersuchungen iiber Propfbastarde. Zeitschr. 
Bot. 1:315-345. pl. r. figs. 4. 1 
