752 NATURAL SCIENCE. 0^,.. 



in his "Samen,Fruchteu. Keimlinge" (Berlin, 1891), describes the seed 

 and seedlings of some of the endemic German shrubs and trees ; but 

 up to the present date seeds and seedlings hav e never been studied 

 in the same systematic way as the adult plants. This deficiency Sir 

 John Lubbock seeks to supply in his " Contribution to Our Know- 

 ledge of Seedlings." 



The two good-sized volumes contain the results of a vast amount 

 of work. Seeds of almost every natural order have been germinated, 

 and the seeds and seedlings, and process of germination, de- 

 scribed. In the case of small orders, or those exclusively tropical and 

 not found in cultivation, it has been possible to give only a few 

 illustrations ; but the large and important temperate or world-wide 

 families have been very thoroughly studied. The arrangement 

 adopted is that of Bentham and Hooker's "Genera Plantarum"; 

 preceding the technical descriptions of the plants of each family 

 is a general account of the fruit and seed considered as bearing 

 on the form of the embryo, and also of the seedlings, while an attempt 

 is made at a classification of the chief types. 



The systematic portion of the work is prefaced by an introduction 

 of nearly 80 pages, in which the author discusses some of the leading 

 points arising from the subject-matter of the twelve hundred 

 pages which follow. The contents of this introductory chapter 

 have already appeared in several papers published in the Journal 

 of the Linnean Society ; they are reproduced here in a revised and 

 connected form. 



The introduction shows what to look out for in the rest of 

 the work, and the explanations proferred of the points here briefly 

 touched' upon will suggest much to those who read the book with 

 any intelligence, and show, moreover, what a mine of wealth lies 

 hidden in the mass of technical descriptions. The author lays stress 

 on the variety in form of the seed-leaves or cotyledons, which though 

 not quite so great as that obtaining in the foliage, is yet surprising ; 

 and also on the striking contrast between the cotyledons and not 

 only the final leaves, but even those by which they are immediately 

 followed. " So far, indeed, are the cotyledons from agreeing with 

 the forms of the leaves, that the difficulty is to find any which have been 

 clearly influenced by them." In some cases, however, it is evident 

 that external conditions acting similarly on both have had a similar 

 result, as, for instance, in the Crassulaceae, where we find the cotyledons 

 observed were all succulent, like the adult leaves and the plants 

 themselves, those of Crassula quadvijida being also similarly covered with 

 glands secreting a white substance ; in both cases the same protection 

 against loss of moisture has been adopted. 



We may contrast these with the drought-loving cactus family, 

 where, as in Opiintia, the cotyledons are fleshy, while the leaves have 

 been reduced to spines or bristles (Fig. i). In Echinocadiis viridescens 

 (Fig. 2), however, it is interesting to find the cotyledons also reduced, 



