444 BIOGRAPHICAL SKETCHES. 



Thus his first monograph was of the genus Cuscuta (pub- 

 lished 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 Cuscutai, 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 difficult, and upon which Dr. Engelmann's author- 

 ity 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," in the latter's memoir of 

 this tour, published by the United States Senate. It was fol- 

 lowed up by his account (in the American Journal of Science, 

 1852) of the Giant Cactus on the Gila ( Cereus giganteus) 

 and an allied species ; by his synopsis of the Cactacece of the 

 United States, published in the " Proceedings of the American 

 Academy of Arts and Sciences," 1856; and by his two illus- 

 trated memoirs upon the southern and western species, one 

 contributed to the fourth volume of the series of Pacific Rail- 

 road Expedition Reports, the other to Emory's Report on the 

 Mexican Boundary Survey. He had made large preparations 

 for a greatly needed revision of at least the North American 

 Cactacem. But, although his collections and sketches will be 

 indispensable to the future monographer, very much knowledge 

 of this difficult group of plants is lost by his death. 



Upon two other peculiarly American groups of plants, very 

 difficult of elucidation in herbarium specimens, Yucca and 

 Agave, Dr. Engelmann may be said to have brought his work 



