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 AdanUc Ocean. Professor Wood, 

 from whose " Class Book " we have taken our description, 

 notes, in 1861, that it was wild abundandy on the shores of the 

 Kentucky river, at Paris, in Kentucky State. In 1S72, 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, nodce 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 

 acquisidon 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 tew 

 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 attenUon. It has in this way become particularly 



