30 BULLETIN UNITED STATES GEOLOGICAL SURVEY. [Vbl.VL 



Fumariace^s. — Three genera, of which only the larger one, Gorydalis, 

 18 amphigfiean. Its species are of Eastern Asiatic rather than European 

 types and relationship. 0. aurea and its kindred forms, rather than 

 species extend across the whole continent and to Japan; the striking 

 species described as C. Oaseana, of the western Rocky Mountains to the 

 Siena, appears to break into analogous forms which have recently been 

 taken for species. Dicentra, peculiar to North America and the Japano- 

 Himalayan floras, lias perhaps a majority of American species. They 

 belong wholly to wooded districts. One species crosses the whole con- 

 tinent along the northern border of our belt; in another case Pacific 

 and Atlantic species hardly at all differ 5 the three or four others are 

 peculiar. Adlumia, the remaining genus, is of a single Atlantic species. 



< kucifer^e. — For an order of over 170 genera and more than 2,200 

 species, North America, in her about 40 indigenous genera, none of 

 over two dozen species, cannot be said to have a large share; and the 

 exclusion of Arctic alpiue forms reduces the number considerably. The 

 Atlantic OruciferaB are almost all European in type; Leavenworthia and 

 Warea are the only peculiar genera. The eastern border of the plains 

 has a local nenus, Selenia, and there begin the characteristic genera 

 Streptanthus and Stanleya, and species of Vesicaria multiply southward ; 

 the I tacky Mountains exhibit no characteristic type, unless it is Physaria, 

 but the arid region beyond begins to share with California in the abun- 

 dance of Lcpidium, and in the several endemic genera, of which Thysano- 

 carpus is the most characteristic. It is the Arizonian region that furnishes 

 the American representatives of the Old Word genus Biscutella, the 

 Dithyrcca of Harvey. 



Capparidace^e. — Within the limits specified North America has 

 no Capparccv, but all the genera of Cleomecv except two are indigenous 

 and the greater part of them peculiar to it — all in the warmer parts, the 

 number of species and types increasing south westward, and extending 

 into Mexico. The peculiar types, Cristatella, CJeomella (of several spe- 

 cies), Wislizenid) and Oxystylis, are characteristic of the southern part of 

 the central region. 



Besedace^e we exclude, believing Oligomeris subulata to have been a 

 Spanish importation. 



Cistace^e. — Two of the four genera of this more conspicuously ori- 

 ental order. Hudsania and Lcchea, are peculiar to the Atlantic States, to 

 which also three species of Hclianthemum are indigenous, and there is one 

 species od the coast of California. The order is wanting to the whole 

 intervening portion of the continent. 



Violace^e. — In species of Viola North America is as rich as the Old 

 World, and the Pacific iloraas rich as the Atlantic and with greater diver- 

 sity of type; a lew species common to each, hut most of them peculiar. 

 The central flora has hardly any except in the alpestrine region, aud these 

 f«\\ and of wide-spread species. A Mexican lonidium reaches Arkansas 

 ami Arizona. 



