386 BOTANICAL GAZETTE [MAY 
Pleurothallis, Habenaria, Pogonia, and Microstylis. The — of species 
in each genus are preceded by determinative keys.—J. M. 
North American flora..—Volume IX, part 3, of this work consists of an 
elaboration of the Agaricales as follows: anetird ee reser by W. A. 
Morritt, and Lactarieae (pars) by . Bur New species are 
described in Gyroporus (1), Citcmyces a ae ‘Suillellan (1). Three new 
monotypic genera of the Agaricaceae are proposed, namely, Polyozellus, Pli- 
caturella, and Chlorophyllum.—J. M. GREENMAN. 
NOTES: FOR STUDENTS 
Graft hybrids.—The question of graft hybrids continues to grow in interest. 
WINKLER’s previous papers on this subject have already been reviewed in this 
journal.*e His latest contribution': deals with the second and later generations 
of the graft hybrids between Solanum nigrum and S. lycopersicum, and with the 
chromosome numbers in these forms. It is found that the different graft hybrids 
fall into a series resembling most one or the other parent, in the following order: 
S. nigrum, S. Gaertnerianum, S. Darwinianum, S. tubingense, S. proteus, S 
Koelreuterianum, S. lycopersicum, the first three graft hybrids being most like 
S. nigrum and the last two nearest S. lycopersicum. In the F, the first three 
revert to S. nigrum, while the sn two produce the tomato. Large numbers of 
offspring were grown in some cases, e.g., 1200 individuals in the F, of S. tbin- 
gense, all of which without ae a were pure S. nigrum. The F; and F, and 
later generations continued true S. nigrum. Regenerated adventive shoots also 
reverted only to the nightshade, but in the case of S. proteus reversions to both 
parents occurred, and in this and other cases various chimeras appeared from 
adventive shoots. S. Gaertnerianum is almost sterile and shows little tendency 
even to parthenocarpy, which is more frequent in some of the others. 
Crosses of the graft hybrids with the cage ie! most resembled gave similar 
results, e.g., S. tubingenseXS. nigrum gave only S. nigrum. Crosses with the 
more distant parent, as S. tubingenseXS. oe failed to produce seeds, 
although peer yy dates ed oecureed: 
Regardin nS. ly | the numbers were 12 (haploid) 
and 24 (diploid), and in S. nigrum 36 and ‘approximately 72, therefore three times 
as many. If a fusion of nuclei took place in the production of the graft hybrid, 
one might expect the latter to have 72+24 (96) chromosomes unless a regulation 
in the number afterward occurred; but this number is not found. Instead, 
S. tubingense, S. Darwinianum, and S. Gaertnerianum were found to have 36 
chromosomes in their pollen mother cells (after reduction), while the other two 
9 North American flora, Vol. IX, part 3. pp. 133-200. New York Botanical 
Garden. 1910 
to Bor. Cuasen 47:84, 250; 48:478. 1909. ae 
rt WINKLER, Hans, Ueber die Nachkommenschaft der Sonn 
und die Chroiasccse ee ihrer Keimzellen. Zeit. Bot. 2:1-38. 1999 
