1913] CURRENT LITERATURE 335 
is comparatively little periodicity. By a series of experimental cultures, 
carried on partly in Java and partly in the greenhouses at Heidelberg with 
tropical trees of periodic habit, he has succeeded, by varying the fertility of the 
soil, in obtaining varying responses from the same species and in greatly 
prolonging the period of continuous growth. This leads him to conclude that 
periodicity may be conditioned by the supply of food materials. He also calls 
attention to the fact that in attempts to relate periodicity to external factors 
only the more obvious climatic conditions have been considered, and that our 
data consist largely of comparatively crude observations. More exact studies 
nm an experimental basis are required. He concludes that the idea of a 
general primary rhythm in tropical plants, as advanced by ScHIMPER and now 
supported by VoLKENs and others, is contradicted by one series of facts, is 
rendered doubtful by other facts, and is supported only by such observations 
o the present time it has been impossible to subject to a searching 
physiological examination—Gro. D. FULLER 
Paleobotanical notes.—WueERRyY" has described three types of fossil wood 
from the Trias of Pennyslvania. The first, Araucarioxylon virginianum 
Knowlton, has been found previously in North Carolina, Virginia, and Con- 
necticut. The second, A. vanartsdaleni, is separated as a new species on the 
lower medullary rays and predominance of uniserial pitting of the tracheids. 
The third is referred to the genus Brachyoxylon Hollick and Jeffrey, under the 
hame of B. pennsylvanicum, sats ek ae pits, when uniserial, are usually 
poered and circular, and when either “distant and sub-opposite”’ 
or “alternate and hexagonal.”’ This SIE seems hardly justified, 
for the pits in Brachyoxylon, when double, are always alternate and closely 
is the formation of traumatic resin canals. Without this reaction, WHERRY 
cannot see refer = specimen to the genus Brachyoxylon. 
In a second paper,!? WHERRY discusses the evidence supporting the sug- 
gestion sige the Oe “New Red” may represent deposits from the Lower 
Carboniferous to the Jurassic, and concludes that while there are no grounds 
for referring any of these beds to the Paleozoic, the absence of distinctive 
fossils except those of the Keuper type leaves it an open question whether there 
may not be also Bunter below and Jurassic above.—R: S. HOLDEN 
Earliest European angiosperms.—Dr. Sropes has described* three new 
genera from the lower Greensand of England, representing the earliest struc- 
turally known European angiosperms. The first, A ptiana radiata, has vessels 
6 Wuerry, Epcar T., Silicified wood from the Triassic of Pennsylvania. 
ed , Age and correlation of the “New Red” or Newark Group of Pennsyl- 
vania. 
"8 Sropes, Marte C., Petrifactions of the earliest European angiosperms. Phil. 
Trans. Roy. Se London B 203:75~100. pls. 6-8. 1912. 
