JVV'. 1.; (n?AY AND IIOOKKIJ ON TllK KOCKY MOUNTAIN FLORA. 35 



iiiid Central Asia, where a great majority of the rest of tlie Antragalece 

 flourish. Amorpha is shared by the Atlantic and Pacific floras. Ther- 

 mo2)S'is, with three local Atlantic species, one in the Eocky Mountains 

 and two in California, has also Eastern Asian species. 



CiESAiPiNEiE. — Excluding- the Texano-Arizonian forms, the only 

 Pacific representative is a single Gercis ; the central region has none, 

 <3xcept, perhaps, a Roffmanseggia or two j while the Atlantic has a G&rcis 

 of its own, rising to the size of a forest tree, also stately trees in Gym- 

 nocladus and Gleditschia (two species), and of herbs a few species of 

 Gassia. 



MiMOSE^ are in nearly similar case. Not one is truly to be reckoned 

 in the Pacific flora or in the Eocky Mountain flora within our proper 

 bounds, though several representatives appear a little farther south; 

 but SchranTciaj a Mimosa, a Nejptunia, and two or three species of Des- 

 maiithus (all herbaceous) come within our limits on the ultra-Mississip- 

 pian plains and barely enter the Atlantic flora. The shrubby or 

 arboreal Mimosece [Mimosa, Frosopis in its two forms. Acacia, &c.) char- 

 acterize the Texano-Mexican bordering district. 



EosACE^. — This imijortant order has very characteristic North 

 American genera. Unlike the preceding order, the western genera are 

 more numerous than the eastern, and also abont as numerons in species. 

 Taken under their suborders or great groups — 



CnRYSOBAiANE^. — Are represented only on the Atlantic coast, and 

 by a single Ghrysohalamis, excluding, of course, the tropical one in 

 Florida. 



Amygdale^. — Occur in the Atlantic flora only under the true Pru- 

 mis, Padus, Gerasus, and Lauro-cerasus sections, except that in Texas 

 forms approaching Amygdalus occur. The Pacific flora has scanty rep- 

 resentatives of the same types. The sonthern and "western borders of 

 the Great Basin are marked by two i3eculiar Amygdalus-like species, 

 Pnimts Andersonii, in which the exocarp falls from the stone in two 

 valves like an almond, and P. fasciculata, on which Torrey founded a 

 genus, Emplectocladus. Then, the Pacific coast has the curious and 

 unique genus NuttalUa, Torr. & Gray, which is regularly pluricari^ellary. 



The true Eosacese have Spircca in several types, Neillia, Eithus, 

 Gsum, Fragaria, Pofentilla, Agrimonia, Poterium, and Eosa, in common 

 over the continent, the species of Potentilla much increasing westward. 

 Peculiar to the Atlantic flora are only Neviusa (of Japanese affinity), 

 GiUenia, and Dalibarda; to the Pacific flora, Ghama^hatia, which abounds 

 over the western slope of the Sierra Nevada, and Adenostoma, which 

 forms a large part of the chaparral or chamisal (the shrub is called 

 '■'■Gliamiso'''') of the foot-hills and coast-ranges. Peculiar to the Eocky 

 Mountain flora, mostly to the Great Basin and to its southward exten- 

 sion into Mexico, are Goleogyne, a single and very local shrub of the 

 desert, Goicania, Fallugia. Peculiar, or nearly so, to the two western 

 regions are Gercocarpns (with one Mexican species) and the two poten- 



