1910] CURRENT LITERATURE 387 
possessed 12 chromosomes. Therefore in both cases the numbers are the same 
as in the parents to which they revert in the F,. This of course does not eliminate 
the possibility that a fusion of nuclei had occurred, and that afterward a regulation 
in the number took place, perhaps just previous to reduction or at the time of 
reduction. 
STRASBURGER™ has made a number of Solanum grafts according to WINKLER’S 
method, and examined the growing tissues along their line of union, to determine 
whether cell fusions take place. He found no indication that such is the case, 
but of course negative evidence in such a matter is inconclusive, for the graft 
hybrids are rare at best. STRASBURGER concludes that WINKLER’Ss cases are 
really complicated chimeras, in which the tissues of the two parents are inti- 
mately blended in the growing points. He proposes to call them “‘hyperchimeras,”’ 
and cites various analogous cases of very intimate relationship, such as between 
parasite and host. 
INKLER, however, is still convinced that these cases are true graft hybrids, 
although concurring in SrRASBURGER’s opinion that Cytisus Adami, which Srras- 
BURGER*S showed to have the same number of chromosomes as its parents, is a 
chimera. He proposes to determine the chromosome number in the somatic cells 
of the Solanum hybrids to see whether it is higher than in the germ cells, and 
contends that, even though no fusion of nuclei occurs, in its absence the effect of 
the cytoplasm of one type of cell upon the other will be necessary to explain the 
production of the characters of the graft hybrids. This view scarcely seems 
hecessary to explain the present facts, but WINKLER’s further cytological papers 
to determine what actually occurs will be awaited with interest. It is hoped that 
full accounts, with figures, will be forthcoming. 
Baur" has reiterated recently his belief that these forms are explainable as 
periclinal chimeras, varying in the arrangement of the layers in the growing point, 
and thinks that the case of Crataegomespilus can be explained in the same way. 
The fact that in these Solanums the number of chromosomes is so unlike 
adds much to the interest of the situation —R. R. GarEs. 
Sexuality of the.rusts.—The differences of nuclear behavior in the rusts as 
described by BLACKMAN and CHRISTMAN have led KurssANow’s to investigate a 
similar form. According to BLACKMAN,"® in the caeoma of Phragmidium violaceum 
the nucleus of a vegetative cell passes into that of a specially differentiated female 
‘2 STRASBURGER, E., Meine spitctares: zur Frage der Pfropfbastarde. Ber. 
aes Bot. Gesell. 2'7:511-528. 1 
, Ueber die ni der Chromosomen und die Pfropfhybriden- 
ies Teoh. Wiss. Bot. 44:482-555. pls. 5-7. fig. I. 1907. 
** Baur, E., Pfropfbastarde, Periklinalchimaren, und Hyperchimiren. Ber. 
Deutsch. Bot. Gesell. 2'7:603-605. 191 
*S Kurssanow, L., Zur Sexualitat der Rostpilze. Zeit. Bot. 2281-93. fl. r. 1910, 
*° BLackman, V. H., On the fertilization, alternation of generations, and the 
Seneral cytology of the Uredineae. Annals of Botany 18: 323-373. 1904. 
