74 BOTANICAL GAZETTE [yULY 
Mendel’s law in violet hybrids.—BramverD33 has given an interesting — 
account of the offspring of supposed violet hybrids which show that certain char- 
acteristics behave according to MENDEL’s law. The characteristics observed 
were the color of the capsule, purple vs. green; and the color of seeds, brown vs. 
buff. The parents of his plants were supposed to be hybrids between Viola hirsu- 
tula and V. papilionacea. With respect to the two characters considered, the 
supposed hybrids should be di-hybrids. The number of F, offspring was only 
twenty-one, but all four of the possible combinations were present and the larger 
number showed the two dominant characteristics, purple c psul rown seeds. 
Several F; families further demonstrated the Mendelian nature of these char- 
acteristics. The writer points out that Mendelian behavior in the offspring of the 
supposed hybrids demonstrates their hybrid character—G. H. SHULL. 
Age of Hepaticae.—CamppBeLt contends3+ that both the Hepaticae and 
Musci are old types, the perishability of their tissues and insufficient search 
accounting for the lack of known fossil remains. He finds in the wide distribution 
of certain genera of Marchantiales and Anacrogynae, and the cosmopolitan dis- 
tribution of many of their species, evidence of the relative antiquity of the groups, 
since these plants are not adapted to rapid distribution. In proof of the latter 
he cites a few experiments, the character of the spores, and the fact that no Hepati- 
cae have been found on Krakatau since the eruption, though Java with an abun- 
dant hepatic flora is in sight. Analogy from pteridophyte and spermatophyte 
distribution is adduced in support of this conception of the significance of bryo- 
phyte distribution. The weakness of the case js evident enough, but certainly 
it is as good as any, if one must speculate.—C. R. B. 
Klinostats.—VaN HARREVELD finds35 by chronographic tests that the klino- 
Stats in use at present are all defective in that they do not secure uniform rotation, 
especially when the axis of rotation is inclined or horizontal and the load is not 
exactly centered. The modern motor-driven forms are the least objectionable. 
This inequality of pace leads to definite and unexpectedly large geotropic responses 
and should therefore be eliminated. To obviate these difficulties, he has con 
structed an instrument upon new principles. It is driven by a weight automat 
cally raised, and it is released under pendulum control by a rachet actuated by 
an electromagnet. The intermittent shock of stopping is reduced by vanes ant 
a wheel train. Photographs and drawings are given and a full description 8 
promised when the instrument has been exhaustively tested.—C. R. B. 
8° BRAINERD, E., Mendel’s law of dominance in the hybrids of Viola. Rhodors 
9: 211-216. figs. 2. 1907. : 
» D. H., On the distribution of the Hepaticae and its significanc’ — 
New Phytol. 6: 203-212. 1907. 
Bas HARREVELD, PH. vAN, Die Unzulanglichkeit der heutigen Klinostatet - 
pO Re ee Untersuchungen. Recueil Trav. Bot. Néerl. 3:173 ff. (pP- < a 
- 3. 1907. 2 
