1907] CURRENT LITERATURE 352 
tively small and has not been found to contain pollen grains. The megaspore 
membrane is distinct, but structureless, and no traces of endosperm or archegonia 
were found. 
. The second part of the paper will be devoted to a discussion of the general 
bearing of the investigation and the probable affinities of the seed. It is to be 
regretted that in such a paper the citation of literature is not more specific. Refer- 
ence merely to volume numbers puts needless work upon those who wish to 
consult the literature.—J. M. C. 
Dorsiventrality in mosses.—NEmMEc has continued his study of dorsiventrality 
induced by light, finding additional species'+ in which this character can be 
altered. The tenacity with which dorsiventrality is retained under changed 
illumination differs widely. Thus in Anomodon viticulosus every flank in turn, as 
more strongly illuminated, may become the dorsal side. In Neckera and Homalia, 
on the contrary, only the dorsal and ventral sides could be made to exchange 
relations. Ageotropic species are usually strongly diaheliotropic (but may become 
positively clinoheliotropic), turning the dorsal side toward light. Geotropic 
species are hindered from acquiring a diaheliotropic position, especially if they 
must curve nearly to the horizontal. The species whose dorsiventrality is not 
reversible sometimes do not attain completely the diaheliotropic position if much 
bending is required. Such incomplete reactions are still more common among 
leafy Jungermanniaceae. 
In a later paper on the same lines’ NEMmeEc deals especially with Fissidens 
spp., and Dicranum scoparium. In Fissidens the dorsiventrality (morphological 
as well as physiological) can be abrogated and recalled at will. The stems are 
also diaheliotropic and geotropic. In Dicranum scoparium the lateral curvature 
of the leaves is a heliotropic response which is induced very early and persists 
for a considerable time even in darkness, but finally disappears, returning again 
with one-sided illumination. ‘The complicated interrelations of geotropism and 
heliotropic dorsiventrality are worked out in detail.—C. R. B 
Galvanotropism of roots.—A paper on this subject, published in September 
1904 by Dr. AMos PLowMAn,’° has come to our attention since writing the notice 
of the papers by SCHELLENBERG and GASSNER.'7. The methods used and the 
conclusions reached are anticipatory, in large measure, of those of GASSNER. 
used carbon electrodes and states the strength of currents used in terms 
of current density, those mentioned lying mostly between 0.1 and 1.5 milli- 
"4 NEMEc, B., Die Induktion der Dorsiventralitat bei einigen Moosen. II. Bull. Int. 
Acad. Sci. Boheme 11: (1-7). 1 
18 NEmec, B., Die Symmetrieverhiltnisse und Wachstumsrichtungen einiger 
Laubmoose. Jahrb. Wiss. 43:501-579- figs. 33- 1906 
wMAN, A., Electrotropism of roots. Am, Jour. Sci. IV. 18:228-236. 
pls. 9, 10. 1904. Also earlier reports ibid. 142131. 1902, and 15: 94-104. 1903. 
17 Bot. GAZETTE 432218. 1907. 
