290 Allgemeines. 



Organs with great weaith of citation of original authorities, and 

 many new figures. The megasporangium is treated in the 

 fourth chapter with equal fuilness. The fifth capter contains 

 an account of the female gametophyte. The figures and cita- 

 tions are particularly numerous in this important chapter, in 

 the case of the latter including 122 titles. Chapter 6 treats of 

 the male gametophyte. hi chapter 7 fertilization is dealt with, 

 and in this connection the authors criticise the term double fer- 

 tilization as applied to the fusion of the second generative 

 nucleus with the polar nuclei of the embryosac, to constitute 

 the endosperm nucleus. They question of the legitimacy of the 

 implication of sexuality in this process conveyed by the term 

 double fertilization, and suggest as a Substitute the phrase triple 

 fusion. The eighth chapter is devoted to the formation of the 

 endosperm, while the ninth treats of the development of the 

 embryo and includes a very füll account of polyembryony in 

 the Anglosperms. The list of literature cited in this chapter in- 

 cludes 95 titles. The tenth chapter is devoted to the Classi- 

 fication of the Monocotyiedons. The authors conclude that there are 

 three primitive monocotyledonous Stocks — Pandanales, Helobiales, 

 and Glumales — and that they are connected with the other alliances 

 as follows: Pandanales — Palmales — Synanthales: Helobiales — 

 Arales: Glumales — Farinales — Liliales — Scitaminales — Orchi- 

 dales. The Classification of the Archlchlamydeae is considered in the 

 next chapter and that of the Sympetalae in the twellth chapter. In 

 the thirteenth and fourteenth chapters the geographical and the 

 geological distribution of the Anglosperms is discussed. Chapter 

 fifteen is devoted to the phylogeny of the Anglosperms, and 

 the authors summarize their views as follows. „The Monoco- 

 tyiedons and Dlcotyledons represent two independant lines 

 directly from Pteridophyte stock, probably from the Filicales. 

 At the same time, the arguments in favor of a monophyletic 

 origin of the Anglosperms are strong and if this view be 

 accepted, the derivation of the Monocotyiedons from the primi- 

 tive Dlcotyledons seems to rest on stronger evidence than the 

 reserve relationship. It must also be said that the Gymnosperm 

 origin of the Anglosperms is not to be so much discredited now 

 as formerly." 



The last two chapters are contributed by Professor E. C. 

 Jeffrey, and treat of the phylogenetic anatomy of the Gymno- 

 sperms and Anglosperms. In regard to the Coniferales the 

 following opinion is expressed. „The Coniferales much as 

 they resemble the Lycopods in external appearance, are really 

 derived from filicinean ancestry by adaptation to a xerophytic 

 mode of life. The microphyllous habit is obviously a ceno- 

 genetic adaptation, for the structure of the fibrovascular skeleton 

 piainly indicates that the coniferous stock is palingenetically 

 megaphyllous, and thus allied to the Ferns." Concerning the 

 probable affinities of the Dlcotyledons this statem.ent is made. 

 „The Dlcotyledons as a group are distinguished anatomically 



