520 GEORGE ENGELMANN. 



day, who compares it with Moquin-Tanflon's more elaborate Teratologie 

 Vegctale, published ten years afterwards, and who declares that, " when 

 we compare the two works from a philosophical point of view, and 

 consider that the one was a mere college essay, while the other was 

 the work of a professed botanist, we must admit that Engelmann's 

 treatise, so far as it goes, affords evidence of deeper insight into the 

 nature and causes of the deviations from the ordinary conformation of 

 plants than does that of Moquin." 



Transferred to the valley of the Mississippi and surrounded by 

 plants most of which still needed critical examination, Dr. Engelmann's 

 avocation in botany and his mode of work were marked out for him. 

 Nothing escaped his attention ; he drew with facility ; and he methodi- 

 cally secured his observations by notes and sketches, available for his 

 own after use and for that of his correspondents. But the lasting 

 impression which he has made upon North American botany is due 

 to his wise habit of studying his subjects in their systematic relations, 

 and of devoting himself to a particular genus or group of plants (gen- 

 erally the more dilTicult) until he had elucidated it as completely as 

 lay within his power. In this way all his work was made to tell 

 eflFectively.. 



Thus his first monograph was of the genus Cuscuta (published in the 

 American Journal of Science, in 1842), of which when Engelmann 

 took it up we were supposed to have only one indigenous species, and 

 that not peculiar to the United States, but which he immediately 

 brought up to fourteen species without going west of the Mississippi 

 valley. In the year 1859, after an investigation of the whole genus 

 in the materials scattered through the principal herbaria of Europe 

 and this country, he published in the first volume of the St. Louis 

 Academy of Sciences a systematic arrangement of all the Cuscuta% 

 characterizing seventy-seven species, besides others classed as perhaps 

 varieties. 



Mentioning here only monographical subjects, we should next refer 

 to his investigations of the Cactus family, upon which his work was 

 most extensive and important, as well as particularly diHicult, and upon 

 which Dr. Engelmann's authority is of the very highest. He essentially 

 for the first time established the arrangement of these plants upon 

 floral and carpological characters. This formidable work was begun 

 in his sketch of the Botany of Dr. A. Wislizenus's Expedition from 

 Missouri to Northern Mexico, m the latter's memoir of this tour, pub- 

 lished by the United States Senate. It was followed up by his ac- 

 count (in the American Journal of Science, 1852) of the Giant Cactus 



