Ifc.1.1 GRAY AM) HOOKEB OH im: ROCKT MOUNTAIN FLORA, 



Rubia< k.i:. — This vast order of ovei 300 genera and 1,000 species 

 forme an insignificant feature in North America, and in the northern 

 temperate /.one throughout Bui the poverty of the Rockj Mountain 

 and the Pacific floras is extreme. There are some species of Galium 

 in all. and Cephalanthus is on both sides of the continent and of south- 

 ern extension. Besides, the Pacific flora has only the peculiar mono- 

 typic genus Kellogg ia, with no mar relative in the northern hemisphere. 

 Atlantic flora nearly monopolizes the genuine species of Houstonia, 

 and its specially characteristic genus is MitcheUa, which is repeated in 

 a \ ei ;« similar species in Japan. 



v.vi.i:i;ia.n \< 1 :.i:. — A small family, is here onimportant. The only 



us is Plectritis of the Pacific coast and that of Chili. 

 ( omposj I i:.-Nn detailed analysis can be expected hereof the dis- 

 tribution of an order which is thonght to make up one-tenth of flowering 

 plants and which composes a still larger proportion of those of North 

 America. Vet a tew points may be brought to view, taking the tribes 

 separately. 



Yhknom.u e.t:. — Are known only in the Atlantic region, the princi- 

 pal genus, Vernonia, however, extending over the prairie border of the 

 plains. StoJceria is one of those strictly peculiar genera of a single spe- 

 ;th which the Atlantic flora abounds. 

 EUPATOBIACE^E. — This is almost an American tribe, the maximum in 

 South America, the minimum in our Pacific Territory, which has only 

 four or live species. But into the Rocky Mountains and the Great 

 ; extends, more largely than into the Pacific Mora, the genus Brick- 

 cilia, founded on an outlying species of the Atlantic flora, yet mainly a 

 mo-Mexican genus. But the Atlantic flora is better supplied, and 

 with peculiai . viz. Sclerolepis^ Trilisia, Carphephorua (the South 



California species is hardly congeneric), the line and rather large genus 

 Liatri8, which, however, reaches nearly to the Rocky Mountains and 

 into Mexico, and Kcltuia, which is in the sane- case, Qarberia of Flor- 

 ida, taken from Liatris, is too southern to be properly counted. The 

 I ^ns Eupatorium is also well represented on the Atlantic side, 

 and here only is the northern extension, in a single species, of the huge 

 ii American genus Mikania. 

 Asteroidejb. — Axe eminently American, and in no other single 



so numerous as in the bell across the contin ait which is 

 under consideration. Aster ^ Solidago^smd Bigelovia are the great ge 

 Aplopappw, Chry Erigeron, and Tawnsendia are next In importance. 



About four- tilths of the AsU raand Solidagos belong to the At lan tie flora, 

 with -nine extension into the plains beyond, and there also are more 

 md forms (but fewer individuals) of Chrysopsis; the ampb 

 oh has its fullest development and dh ersification in our west- 

 Aplopappu* is divided between our Koekj Mountain 

 with southward ex ten -inn and into that of tin and that of Chili. 



;he most chat enera of tin- * hole 



