78 EUPHORBIA MARGINATA.—SNOW ON THE MOUNTAIN. 
work. Reference is made to this fact in order to furnish a 
lesson in Botanical Geography. The home, as we may say, of 
our plant about fifty years ago, was in the drier parts of our 
country, between the Missouri and the Rocky Mountains. 
Since that time it has progressed eastward rapidly, and it is 
more than probable that at no very distant date it will be found 
wild up to the shores of the Atlantic Ocean. Professor Wood, 
from whose “Class Book” we have taken our description, 
notes, in 1861, that it was wild abundantly on the shores of the 
Kentucky river, at Paris, in Kentucky State. In 1872, Pro- 
fessor Bessey notes, in the “American Naturalist” for that year, 
that it was then in great abundance in west and northwestern 
Iowa, and Mr. Arthur includes it now in the regular catalogue 
of the Flora of that state; and in the “Bulletin of the Torrey 
Botanical Club” for 1876, we find Mr. R. Burgess noting that it 
was abundant along the Missouri valley in Missouri. In regard 
to Indiana, notice of its existence is recorded, so early as 1870 in 
the “ Botanical Gazette,” as abundant at Madison; and the same 
season its first appearance at Logansport is recorded in the 
same magazine. This shows how it is marching on to the 
acquisition of more territory, and as of course only one plant 
can exist on the same spot, other species of plants are eventu- 
ally crowded out by the intruders. But it is quite probable that 
the plant did not exist in any great abundance, even in its 
natural home, till civilized man came to its aid. It does not 
flourish remarkably well when struggling with the regular flora 
of the same region; but when the railroad was made and the 
earth in various ways disturbed, the plant appeared in such 
abundance, that the untutored observers thought it must have 
sprung from seed that had lain in the ground dormant for cen- 
turies. But the facts in these and similar cases are that a few 
plants spring from chance seeds, and, being so few, produce 
seeds unobserved; these seeds falling on soil just suited to 
them nearly all grow, and then by their unusually large num- 
bers attract attention. It has in this way become particularly 
