198 THE JOURNAL OF BOTANY* 



dealing in succession with the root, stem, leaf, and flower. While 

 this method has the advantage of correlating structure and function, 

 it leads to a somewhat disjointed study of plant-physiology and 

 involves some repetition. The chapter on the flower is followed by 

 one on " the development of the Phanerogams," in which the deve- 

 lopment of the ovule, the seed, and the fruit, germination, and the 

 growth of the adult plant from the seedling are considered. The 

 formation of the egg and the life-history of the plant in the Vascular 

 Cryptogams, the Muscinese and the Thallophytes are studied in the 

 next tliree chapters. To emphasize the diiferences in the origin of 

 the " spores " in the several great groups, the term spore is restricted 

 to those which develop to form an individual like that from which 

 they were produced. The spores of Ferns and Mosses are designated 

 respectively, diodes, or spores of passage from the asexual to the 

 sexual stage, and tomies, as the life-history of the plant is cut into 

 two very unequal parts at the stage of their production. The 

 relation between the Gymnosperms and Vascular Cryptogams is 

 recognised, the pollen -grain being in reality a microdiode and the 

 mother-cell of the female prothallium a macrodiode. 



The second volume is a systematic study of .the plant-kingdom. 

 Two subkingdoms are recognised, Arhizophj^tes, including Thallo- 

 ph^^tes and Muscinese, and Khizophytes, including Vascular Cr}'3)togams 

 (Exoprothallees) and Phanerogams (Endoprothallees). The Thallo- 

 ph^^tes contain two classes, Fungi and Algae ; the Myxomycetes 

 form the first order of the Fungi and the Bacteria are regarded 

 as a famil}^ of the Blue-green Algaf. Phanerogams comprise two 

 classes, Astigmatees or Gymnosperms and Stigmatees or Angio- 

 sperms. The former has four classes, Pteridosperms, Natrices with 

 motile male cells, including C^^cads and Ginkgo, Vectrices (Coniferie\ 

 and Saccovulees (ovule enclosed in an ovary which forms a sac with 

 no style) — including Welwitschia, Eijlicdra, and Gnetiim. The 

 Angiosperms have three classes. Monocotyledons, Liorhizal Dicot}^- 

 ledons, and Dicotyledons. The second is a very unnatural group, 

 comprising two orders. Grasses and Nympha^aceje ; the Grasses are 

 regarded as having two cotyledons and the water-lilies are classed 

 with them owing to the similarit}^ of the mode of development of 

 the piliferous layer of the root. The method of the grouping 

 of the families of Dicotyledons is widely different from that of 

 other well-known systems. Special stress is laid on the details 

 of the structure and development of the ovule, wdiich Van Tieghem 

 had studied exhaustively. The resulting system may interest the 

 student as an exercise in taxonomy, but cannot be regarded as an 

 advance towards a natural system or a contribution to the study of 

 phylogeny. A. B. 11. 



Standard Cyclopedia of Horticulture, Vol. VI. S-Z. with Supple- 

 ment, pp. 3013-3639, figs. 3516-1056. Edited bv L. H. Bailey, 

 1917. 



The present volume is the last of the imposing work edited by 

 L. H. Bailev, the dovcn of American scientific horticidturists, who is 



