U8 BOTANICAL GAZETTE. 



allied in its species to Eastern Asia, a fact brought out not only by a 

 similarity in common species or large genera, but in very many cases 

 by peculiar species and genera represented by two species only, one 

 in Eastern America, the other in Eastern Asia. In Western America 

 there is no such resemblance, making a greater difference between 

 the floras of the eastern and western parts of the United States than 

 between Eastern America and Eastern Asia. In the west there is a 

 large commingling of Mexican or Southern species that have crept 

 northward, guided by the mountain ranges. Hence the conclusion is 

 arrived at that the similarity between the species of Eastern America 

 and Eastern Asia is explained by the continuity of the continents to 

 the north in the Cretaceous or Miocene and a consequent comming- 

 ling of species, and that the Glacial period drove these species south- 

 ward along the two continents farther even than they appear now. 

 With the retreat of the glacier and the return of a milder climate 

 these plants would creep northward again, but the enormous height 

 of the Rocky Mountain and Sierra Nevada regions would retain the 

 glaciers there long after they had disappeared from the eastern half 

 of the continent. When eventually these alpine glaciers did suc- 

 cumb to a milder climate, the old Asiatico-American species having 

 either established themselves elsewhere or been driven into the sea 

 towards the south, the field would be clear for the advance of the 

 Mexican forms and we find them even up in British America. Hence 

 to state it all in one sentence, our Eastern flora has come from the 

 North and our Western flora from the South. — J. M. C. 



Oaucalis Antheriscus. — I have found thoroughly naturalized in the 

 woods back of Cincinnati and remote from dwellings, Caucalis Anth- 

 eriscus. The name was kindly furnished by J. W. Congdon. Prof. 

 Watson, to whom I sent a specimen, informs me that the plant was 

 found in 1872 by Judge G. W. Clinton, near Buff'alo, N. Y. It is 

 firmly established in this locality and promises, I think, to become a 

 troublesome weed. — C. G. Lloyd. 



Note on Panicum littorale, Vasey, by Gen. Wm. Munro. — Pani- 

 cuM littorale, Yasey, is undoubtedly \ 'repens, L., — one specimen 

 the dwarfish form which he described in the second edition of Sp. 

 Plant, p. 87. It is absolutely identical with specimens which I have 

 before me in DeCandolle's herbarium from Crete and Gibralter, where 

 I have also collected it myself. It is also P. arcnarium, Brotero. 



There has always been considerable confusion about P. repens, L. 

 The P. repens ot Burman, Fl. Ind., p. 2G, tab. 11, fig. 1 (1768), where 



