88 BOTANICAL GAZETTE [yULY 
think that the chief factor in the evolution of the now dominant pinnate type 
of leaf to have been the development of the petiole. Since among woody 
plants the more ancient multilacunar type of node predominates in temperate 
regions, and the palmately lobed leaf among such plants is also almost entirely 
confined to temperate regions, they infer that angiosperms first appeared under 
climatic conditions more temperate than tropical, a climate in the Mesozoic 
probably found only in the uplands. Furthermore, such evidence from leaves 
indicates that the angiosperms have come from the palmate coniferous stock, 
rather than irom the pinnate cycadean stock; and also that the monocotyledons 
were derived from some ancient palmate group of the dicotyledons.—J. M. C. 
Seeds of PON Penne id tetas has eloneren ues seeds of repre-_ 
sentative genera of P. nd has reache g conclusions. 
He finds that the outermost ane of the nucellus ‘Suen, transformed into a 
nutritive jacket before iertilization, and that this layer apparently carries food 
material from the chalazal region to the developing endosperm. He also 
describes the growth of the endosperm by the activity of a “cambium-like 
layer,” which is differentiated very soon after cell formation begins, and also 
calls attention to the varying position of the embryo in reference to the other 
structures of the seed. He concludes that in the germination of certain of the 
seeds which were investigated from this standpoint, the aleurone layer has a 
digestive function, secreting a ferment which converts the starch of the endo- 
sperm into available form sor translocation. In some cases also the absorbed 
carbohydrate is temporarily reconverted into starch in the tissues of the 
embryo, the cotyledons being the principal storage region.—J. M. C 
ssil cycads.—Miss Hotpen* has studied the cetimete between 
that the pinnules are not narrowed, but if anything broaden at the point of 
attachment to the rachis. iss HoLpEN reaches the interesting conclusion 
that Pseudocycas belongs to Bennettitales, as judged by the character of the 
stomata and = epidermal cells. S$ rther concludes that the presence of a 
Pseudocycas rene be applied only to leaves whose cuticular structure is 
known.—J. M. C. 
3° Woopcock, E. F., Observations on the development and germination of the 
seed in certain Polygonaceae. Am. Jour. Bot. 1:454-476. pls. 45-48. 1914 
st HoLpEN, Ruta, On the relation between Cycadiles and Pseudocycas. New 
Phytol. 13:334-340. pl. 3. fig. I. 1914. 
