476 BOTANICAL GAZETTE [JUNE 
BENECKE®*® has presented a concise review and discussion of several of 
the more recent researches upon the influence of metallic salts upon organisms, 
He well points out that what is most needed now is a study of the effect of a 
large number of salts upon the same organism, so that comparison may be 
instituted. He also calls attention to the fact that the effect of salts upon 
other processes than growth (e. = photosynthesis, transpiration, etc.) will 
need to be studied.— B. E. Livin N 
OLIVER," in studying certain unreferred seeds of the Permocarbonif- 
erous, has found that those named Trigonocarpus and Polylophospermum, 
both being of the radially symmetrical type (Radiosperms), agree essentially 
in structure with Stephanospermum and the Trigonocarpons of the English 
oal Measures, having the broad pollen-chambers, the tracheal mantle, and 
the differentiated testa. The probabilities are becoming stronger that many 
of these numerous unreferred seeds belonged to that anatomically differ- 
entiated group Cycadofilices, and it remains to be seen how much of it will 
pass over into the recently proposed group Pteridosperms.*—J. M. C 
ILTIS** has investigated the influence of light and darkness on the rate of 
growth of the adventitious roots of a number of water plants. His results 
show that the growth of the roots observed is decidedly accelerated by dark- 
ness. The mean result of experiments on the roots of five water plants, viz: 
Myriophyllum proserpinacoides, M. verticillatum, Lysimachia nummularia, 
Ranunculus aguatilis, and Elodea canadensis, though varying foniidacabe 
among themselves, shows the growth in length in darkness is approximately 
twice that of similar roots in the light. This is a greater acceleration for 
darkness than has been obtained for soil roots.— W. B. MACCALLUM. 
APOGAMOUS PROTHALLIA” of Nephrodium, showing remarkable nuclear 
changes that appear to be related to the apogamy in question, are described 
in a preliminary note by Farmer, Moore, and Miss Digby. Binucleate cells 
tiguous cell is destitute of a nucleus. Nuclei were also seen passing from 
one cell into another and a fusion of nuclei may then take place, though the 
two nuclei often remain separated for some time. Mitoses in apogamous 
ENECKE, W. VON, Einige neuere cup erg iiber den Einfluss von 
iam. auf Organismen. Bot. ung 627: 113-126. 1904. 
ss OLIVER, F, W., Notes on Zrigonocarpus Brongn. and iperna esas 
Brongn., two genera of palaeozoic seeds. New Phytol. 3: 96-104. pl. 2 
5 See Bot. Gaz. 37: 236-238. 1904 
**ILTIs, HuGo, Ueber den Einfluss von Licht und Dunkel auf das Langenwach- 
stum der Adventivwurzel bei Wasserpflanzen. Bei. Deutsch. Bot. Gesells. 2x : 508— 
517. 190 
7 FARMER, J. B., Moore, J. E. S., and Dicsy, Miss L., On the cytology of 
apogamy and apospory. I. Preliminary note on apogamy. Proc. Roy. Soc. London 
71: 453-457. 1903. 
