1910] CURRENT LITERATURE 477 
Seedlings of Cactaceae.—Among the Cactaceae certain members, Sette 
the genus Pereskia, have a seedling with two fairly thin cotyledons and a slen 
hypocotyl; while others, as Mamillaria, have minute cotyledons and a dais 
_ hypocotyl. Miss DEFRaArtNE%° finds that the mode of transition from stem 
structure to root structure in these two groups is different; in other words, the 
adaptations to environment shown by the adult plants has spread to the seedlings, 
and has also had an effect on the internal structure. Since some species show a 
pair of bundles in the hypocotyl, a comparison is instituted with the liliaceous 
genus Anemarrhena, in which the same condition appears. The presence of 
the double bundle in the cotyledon of this genus has been used by Miss SARGANT 
as the basis of her argument for the derivation of monocotyledons from dicoty- 
ledons by fusion of the two cotyledons, but Miss DEF RAINE finds the origin of the 
double strand in the Cactaceae so various that she considers the validity of the 
argument to be seriously weakened. A number of interesting points of detail are 
recorded in the paper, supplementing the work of GANONG?’ on the cactus family, 
—M. A. CuRYSLER 
Foliar gaps of Osmundaceae.—JEFFREY’S Pteropsida are characterized by the 
presence of leaf gaps, but it has been urged by some recent investigators (notably 
Kipston and GwWyNNE-VAUGHAN) that they are absent frequently in the Osmun- 
daceae. Srvnotrs® has undertaken to investigate this group, and concludes that 
leaf gaps are always present. In the six living species studied a number of cases 
of mature stems were observed im which the gap did not become complete for 
some time after the departure of the leaf trace, “which thus at first seemed to go 
off in a gapless manner.’”’ All of the known fossil Osmundaceae with true 
parenchymatous pith show leaf gaps, with one exception, and this is explained 
as ‘‘a form with very short and narrow gaps, which have been largely obliterated 
in the process of fossilization.”” In all the young plants investigated, leaf gaps 
were evident from the earliest stages. Putting together the testimony from 
fossil and living forms, and also the juvenile and mature stages of the latter, the 
conclusion is reached that the presence of leaf gaps is a primitive feature of the 
Osmundaceae, and that they are placed properly among the Pteropsida.—J. M. C. 
Embryo of Pinus Pinaster.—Saxton*®® has studied the development of the 
embryo of this species as it grows in Cape Colony. The general results are as 
36 DeFRratng, E., The seedling structure of certain Cactaceae. Annals of Botany 
24:125-175. 1910. 
37 GANONG, W. F., Contributions to a corinne a of the morphology and ecology 
of the Cactaceae. Annals of Botany 12:423-472. Pl. 1898. 
INNoTT, EpMuND W., Foliar gaps in the Osmundaceae. Annals of Botany 
24:107-118. pis. II, 12. 1910 
39 Saxton, W. T., The development of the embryo in Pinus Pinaster Soland., with 
some notes on the life history of the species in Cape Colony. S. African Jour. Sci. 
6:52-59. pl. 2. 1900. 
