448 Bibliographical Notices. 



sion is made to the essential difference between the dicotyledons and 

 monocotyledons arising from the union or independence of their com- 

 ponent parts. The cambium regions of the fibro- vascular bundles 

 of dicotyledons are blended into a ring beneath the bark, and in their 

 growth are capable of forcing this outward and forming new layers 

 of wood ; the cambium regions of the isolated bundles of monocoty- 

 ledons (which are not " dispersed confusedly") are buried in the 

 substance of the general parenchyma, and only capable of develop- 

 ment up to a certain point ; consequently these latter cannot enlarge 

 the diameter of the stem to any considerable extent, but merely ren- 

 der it more dense and compact. 



In a note on morphology the author speaks of the ovules as deve- 

 loped from the margins of the carpellary leaves. The existence of 

 a doubt at least, on this point, in regard to many cases, should have 

 been indicated, considering the high names of the supporters of the 

 opposite opinion. 



The integuments of the seed are here said to consist of three 

 layers, viz. " episperm, mesosperm, and endosperm," or in other 

 terms, " testa, sarcosperm, and endopleura." Now the integuments 

 of a seed are two : the testa formed from the primine, and the en- 

 dopleura or membrane interne formed from the secundine. The word 

 episperm is usually applied as a general term to include both coats ; 

 the word endosperm is applied to the albumen. Some indeed pro- 

 pose to call the albumen episperm when formed between the embryo - 

 sac and the endopleura, and endosperm when formed within the 

 embryo-sac, but no such term as sarcoderm is now recognised. 



The physiology is treated rather obscurely. The old notion of the 

 excretion of useless matters by the roots is taken for granted ; and 

 the respiration and digestion described as opposite processes, since 

 respiration is regarded as an inhalation of oxygen with a liberation 

 of carbonic acid, taking place in the dark, while growth or nutrition 

 is said to " consist in varied combinations of oxygen, hydrogen, car- 

 bon and azote, got from the air and water," forming proximate prin- 

 ciples, such as sugar, gum, starch, &c. If nutrition, especially so- 

 called, consists in this, it is difficult to see what digestion and respi- 

 ration are for. 



The manner of growth of cells is summed up very briefly, being 

 said to take place by the development of new ones from " certain 

 germs or cytoblasts affixed to the wall of each." Such statements 

 as these are worse than no account at all of such matters. 



The second section is devoted to classification, and gives the Lin- 

 naean system with an analytical tribe of DeCandolle's Natural system ; 

 and four pages are devoted to the geography and medicinal proper- 

 ties of plants. 



Seven plates accompany the text, not very artistic, but sufficiently 

 clear for those who are satisfied with diagrams. 



