40 The Vegetation of the 



Chenopodium album L. and hybridum L. — The American botanists 

 took those plants unanimously for immigrated ones. Amongst the fifty- 

 five species described by Mocquin in Prodromus XIII., 2, are only two, the 

 exclusive habitat of which is conceded to North America, one in Califor- 

 nia, the other in Carolina and Texas; the species of the genus are equally 

 distributed all over the globe, and the species in question are cosmopolites, 

 the original home unknown; they may have spread by colonization in 

 settled countries, but recently both species were found in the Rocky Moun- 

 tains of Colorado in an altitude of 10,000 feet (Porter & Coulter, Flora of 

 Colorado, 110), C. album L. from the Great Bear Lake, 66° N. L. to Nevada, 

 and C. hybridum L. from the Saskatchewan to the Wahsatch Mountains. 

 Watson (in King's Report, Y. 287), declares both to be indigenous, and 

 in his Revision of N. Am. Chenopodiacese (Pr. Am. Ac. IX, 97), under C. 

 hybridum, he says: " Introduced eastward, but indigenous from Kentucky, 

 Texas, and New Mexico to Oregon." I never doubted that the variet}^ 

 viridis be indigenous, as it is found in our vicinity only in the shade of 

 the woods. 



Amarantus retroflexus L. and albus L. — These species, too, were ever 

 taken for immigrated plants. To Mocquin it is an open question, whether 

 the former came to Europe from America, as to the latter he is sure of it: 

 he gives as habitat Pennsylvania and Virginia. In the meantime the 

 plants were found in the deserts beyond the Rocky Mountains, " far from 

 cultivated fields," as Watson remarks in King's Report, and "probably 

 indigenous." De Condolle did not include them in the list of immigrated 

 plants in Geogr. Botan. 



There is a third species, A. blitoides Wats., which I first observed 

 about ten years ago, when I took it for a variety of A. albus. Now it 

 grows in immense numbers around houses. Watson described it as a new 

 species (Flora of California, II., 41), "Mexico to Northern Nevada and 

 Iowa, and spreading then eastward." As its migration seems to be spon- 

 taneous and steady, and being a North American plant, I ranged it in the 

 list of indigenous plants. 



Poa annua L. Poa compressa L. and Poa pratensis are no doubt cir- 

 cumpolar. They occur from Europe through Siberia to Karatschatka, 

 Poa annua in Sitka (Alaska), after Ledebour (Flora Rossica IV., 372-78), 

 in Greenland and Iceland, after Martens (Fl. arct.), P. Pratensis in Green- 

 land, Iceland and Labrador, Poa compressa in Labrador, after Meyer (Plant* 

 Labrad., 19). So we may have the plants from the North as well as from 

 the East. 



Panicum crus Galli L. is a cosmopolite, the original home of which to 

 verify will hardly be possible; it occurs throughout North America, even 

 in the deserts of Utah and Nevada. 



Agrostis alba L. and A. vulgaris With., have the same distribution as 

 the three species of Poa. They are in Gray's Manual acknowledged as 

 indigenous. 



