338 Anatomie. — Descendenz und Hybriden. 



bable, it seems clear that the Monocotyledons have been derived 

 from the more primitive Dicotyledons. e. C. Jeffrey. 



Jeffrey, Edward C, The comparative anatomy and phy- 

 logeny of the Coniferales. Part. II. The Ahietlneae. 

 (Mem. Boston. Soc. of Nat. Hist. Vol. VI. No. 1. 1905. 

 p. 1—37. pls. 1—7.) 



Upon evidence from anatomy and experimental morphology 

 the author divides the Abietineae into Pineae and Abieteae. 

 Resin canals occiir in the cortex and secondary wood in the 

 iormer, but are absent in the latter except occasionaly 1. in 

 the wood of the female reproductive axis, 2. in the first an- 

 nual ring of vigorous shoots of sexually mature trees, and 3. in 

 the secondary wood of injured stems. The cone scales are 

 persistent in the former subfamily but deciduous in the latter. 

 The persistence of the resin canals in the regions named, and 

 their reappearance as the result of injury lead to their being re- 

 garded as primitive for the group; they are replaced by resin 

 cells in the more highly specialized genera. From a considera- 

 tion of both sporophytic and gametophytic structures it is con- 

 cluded that the Abietineae are an older group than the Ciipres- 

 sliieae^ and on account of the double leaf trace are to be re- 

 lated to the Cordiatales and other groups of the older Gym- 

 nosperms. M. A. Chrysler. 



Sargant, Ethel, The Evolution of Monocotyledons. (Botan. 

 Gazette. XXXVII. May, 1904. p. 325—345.)) 



The writer points out that in the pseudomonocotyledonous 

 Dicotyledons, i. e. those Dicotyledons which possess but a 

 Single seedleaf, there is present in all cases a geophilous tube- 

 rous primary stem and that the same feature is characteristic 

 of nearly all Dicotyledons in which the seed-leaves are even 

 partially fused. She further points out that the peculiar anatomy 

 of the Monocotyledons can best be understood as the result of 

 the broad insertion of a number of close ranked leaves on a 

 squat geophilous stem, Sheis of the opinion that the best hypothesis 

 explanatory of the evolution of the Monocotyledons is that, 

 which derives them from a dicotyledonous ancestry by the 

 assumption of the geophilous habit, and in this connection 

 notes that it is precisely the geophilous habit which brings 

 ahout the greatest similitude to Monocotyledons in the case of 

 the Dicotyledons. E. C. Jeffrey. 



Stone, W., Racial Variation in plants and animals, 

 with special reference to the violets of Philadel- 

 phia and vicinity. (Proceedings of the Academy of Na- 

 tural Sciences of Philadelphia. LV. p. 656 — 699. pl. 31 — 39. 

 October, 1903.) 



