INTRODUCTION. 



11 n'y a qu'une maniere d'avancer les sciences, c'est de les Biniplifier ou d'y 



ajoutcr quelque chose de nouveau." — Poinsot. 

 ' We must not, like children, receive the opinions of our fathers, only because 



our fathers held them." — Mabcus Aurelius. 



For the first idea of this book we are indebted to the much- 

 regretted philosopher, to whose memory it is dedicated. In the 

 Introduction to his Traite d' Organogenie Comparee de la Fleur, Payer 

 says : " In a kind of illustrated Genera Plantar am, undertaken 

 about ten years ago, and which I hope will be published before 

 long, I shall show, by numerous applications, the great importance 

 of organogenic studies in demonstrating the true affinities of plants 

 to each other." For this purpose he had prepared a large number 

 of cuts, which he left to us. Of the text of the work and the plan 

 the Author proposed to follow, we unfortunately know nothing. 

 All that we have to guide us is the essay published under the 

 modest title of Lec^ons sur les Families Naturelles des Planies, a 

 work interrupted in 1860 by his premature decease, and continued 

 by us till the present time. It is, however, probable that the very 

 rich organogenic lore of the author would have entered very largely 

 into the composition of the book. 



That Payer himself should not have been able to execute his 

 stupendous project is no doubt a cruel injury to science. But from 

 the severe lessons of death we learn at least this much, that to 

 raise such a monument to science it is important to begin its exe- 

 cution early. He who does not shrink from such an enterprise 

 may from the commencement hope, either that he himself will be 

 able to crown his work, or that, if few be the days allotted to him, 

 he wdll leave a firm foundation upon which those who succeed him 

 may build. In this case the plan will be traced out, and those 

 who continue the work will be able to conform to it, the key 



