Asa Gray. 193 



descriptive work including all species growing east of the Mis- 

 sissippi and north of Tennessee and North Carolina. It was 

 first issued in 1848, and its fifth and last edition in 1868. The 

 "'Elementary Lessons in Botany and Vegetable Physiology," 

 also, was published first in 1868, as an accompaniment to the 

 Manual, and has had its five editions at nearly the same dates. 

 The first volume of another companion work to the Manual 

 was issued in 1848 — his " Genera Illustrata," containing de- 

 scriptions of the genera of the United States Flora, with illus- 

 trations of great beauty by I. Sprague ; and in 1849 a second 

 volume was published, carrying the works nearly to the Leg- 

 uminosse ; and here it stopped, on account, mainly, of the 

 expense. His " Field, Forest and Garden Botany," a useful 

 flora for schools, came out in 1868 ; and the charming smaller 

 volumes " How Plants Grow," and " How Plants Behave," re- 

 spectively in 1858 and 1875. The latter was prompted by 

 Darwin's works on Insectivorous Plants, the Orchids, and 

 Dimorphism, and both are well adapted to the young student 

 and all uninitiated readers.* 



Besides . the subjects of Gray's investigations already men- 

 tioned, two others of a wider philosophical character interested 

 him deeply : one, in which he was pioneer, the other, the Origin 

 of Species, after Darwin. 



The first of these subjects was the Geographical Distribution 

 of Plants, and particularly the species of the Northern United 

 States both within and beyond the bounds of the continent, and 

 the bearings of the facts on variation and origin. 



His first paper on the subject is contained in volumes xxii 

 and xxiii of this Journal, the numbers for September, 1856, 

 and January and May, 1857. It was written partly in compli- 

 ance with the request of "an esteemed correspondent " for a 

 list of American alpine plants, who, as now appears, was Dar- 

 win. Darwin's Life contains, on page 420, the letter, and shows 

 that its date was April 25, 1855 ; and, also, a second letter of 

 June 8, 1855, which opens thus : " I thank you cordially for your 

 remarkably kind letter of the 22d ult., and for the extremely 

 pleasant and obliging manner in which you have taken my 



* A list of Dr. Gray's publications will be given in another number of this 

 Journal. 



