V 



the study of the forms of cultivated plants under his charge. He 

 was always occupied with the elaboration of careful dissections and 

 descriptions of new and interesting genera and species of plants. He 

 was an admirable draughtsman, and the " Traite General de Bota- 

 nique, Descriptive et Analytique," which he published in conjunction 

 with Le Maout in 1868, is a perfect treasure-house to the student, 

 enriched on every page with the results of his minute and careful 

 observations and the work of his accurate pencil. 



Besides this elaborate review of the whole vegetable kingdom, 

 Decaisne published many useful contributions to detailed systematic 

 botany. Amongst these may be mentioned his classical memoir on 

 the Lardizabalece (1837), that on Pomacece, and the Asclepiadece and 

 Plantaginece, elaborated for De Candolle's " Prodromus." 



To the period of his attachment to the herbarium of the Jardin des 

 Plantes belong his few but standard contributions to phy to geographic 

 literature. These include papers on the plants of Arabia Felix, Egypt, 

 Sinai, and Timor. Morphological botany owes to him, besides the 

 memoir on madder already mentioned, a well-known research (1841) 

 on the development of the pollen and ovule and the structure of the 

 stem of mistletoe (Viscum album), and a study on the floral organogeny 

 of the pear (1857), the excellence of which shows how much Decaisne 

 could have done in this branch of botany had his circumstances and 

 leisure allowed him to devote more attention to it. 



In 1842, on the death of Guillemin, he was associated with Adolphe 

 Brongniart in the editorship of the botanical part of the "Annales 

 des Sciences Naturelles," and on the death of the latter became sole 

 editor. In 1847 he was elected a member of the Institute, taking the 

 place of Dutrochet. In 1864 he was President of the Academie des 

 Sciences ; and in 1877 was elected a Foreign Member of the Royal 

 Society. He was one of the principal founders of the Botanical 

 Society of France in 1854, and as long as health allowed was an 

 assiduous attendant at its meetings. 



The note of Decaisne's scientific work was patient and laborious 

 observation of facts. He was one of those whose life was spent in 

 making sure the foundations of taxonomic botany, and every subse- 

 quent worker will build the more securely for what Decaisne has 

 done. That his mental character was essentially precise and matter- 

 of-fact is merely what we should expect from the direction of his 

 work. From this no doubt it followed that the doctrines of evolution, 

 which in England and Germany have given a new impulse to biolo- 

 gical study, interested him little. Not that his mind was wanting in 

 flexibility to new ideas : he warmly supported the investigations 

 made by Bornet in confirmation of Schwendener's theory as to the 

 nature of lichens — a view which has met with much opposition from 

 the older botanists who are, for the most part, unwilling to abandon 



