1911] CURRENT LITERATURE 153 
That there is an interchange of material between nucleus and cytoplasm 
probably all cytologists will admit, although optical evidence is at present 
very scanty. It seems quite possible that the whole graft hybrid and chimera 
question, when the cytological evidence is all in, will emphasize rather than 
weaken the theory that the nucleus is practically the sole bearer of hereditary 
characters. 
In his most recent account of the chromosomes of these forms WINKLER™ 
finds that Solanum tubingense, S. proteus, S. Koelreuterianum, and S. Gaert- 
nerianum are periclinal hybrids; while S. Darwinianum, at least in the subepi- 
dermal layer of the stem apex, is a fusion bybrid (Verschmelzungs-Propfbastard). 
The germ cells of this latter form have 48 chromosomes, and since the parents 
(S. nigrum and S. Lycopersicum) have 12 and 36 chromosomes as the reduced 
numbers, WINKLER infers that the subepidermal layer from which the pollen 
is derived must have 48 chromosomes; and he supposes that a S. nigrum cell 
with 24 chromosomes has fused with a S. Lycopersicum cell with 72, giving rise 
to a nucleus with 96; and that in the progeny of this nucleus the number has 
become reduced to 48. Another reduction would then give the required 24. 
This seems too complicated to be correct. 
It is evident that cytological investigation of graft hybrids has only just 
begun. STRASBURGER early recognized the importance of such investigation, 
and WINKLER’s splendid success in securing the grafts has reopened an attract- 
ive field for cytological research. -The problems are so numerous and the 
time demanded for reliable results is so great that one man cannot hope to 
do all the work. Many have tried to find out whether there is a cytological 
basis for Mendelism. DrVrtes has welcomed cytological investigations of 
mutation and has generously furnished material for such work. If WINKLER 
should welcome others into the field, the facts might soon be uncovered; but 
if others must wait until he has finished, the task is so great and so complicated 
that, although a young man, he might grow old with the problem still unsolved. 
—CHARLES J. CHAMBERLAIN. 
Plant diseases.—C yanospora albicedrae, a new generic type, is reported on 
the mountain cedar of Texas by Heatp and Wotr.” The fungus is a pyre- 
nomycete of a peculiar type, having its perithecia prostrate, with the short 
osteolum curved outward. The perithecia occur singly or in small groups 
on whitened areas on the trunks and branches. This whitening of the bark 
is the most characteristic symptom of the infected trees. The fungus is sup- 
posed to be a parasite, although its parasitism is not certain. de present 
paper is limited to a description of the fungus and its effect on the 
new Macrophoma (M. Phoradendri) on Phoradendron cen (Pursh) 
8 WINKLER, HANS, Ueber das Wesen der Propfbastarde. (Vorliufige Mitteilung.) 
Ber. Deutsch. Bot. Gesell. 28: 116-118. 1910. 
 Heatp, F. D., and Wo tr, F. A., The whitening of the mountain cedar, Sabina 
sabinoides (H. B. K.) Small. Mycologia 2: 205-212. pl. 31. figs. 3. 1910. 
