BOTANICAL INFORMATION. 23 



In the narrow river-valleys, are oases of Poplar with thickets 

 of Willows, Amorpha frutescens and Rosa ! Rarely is found a 

 thicket of Shepherdia argentea, Elceagnus, Ribes aureum, and 

 Rhus trifoliolata ! In the desert plains, oases of Populus 

 betulcefolia, Pursh, without undergrowth, are very rarely met 

 with ! — Apparent centre of the Astrayalinm of North Ame- 

 rica ! — of the Composite ; — Anthemidece I — Shrubby Arte- 

 misia and Chrysocoma .' — Avenacea; Festucacece and Hordea- 

 cea, most abundant in the genera Stipa and Eriocoma, 

 Festuca and Kcelera, Triticum and Elymus ! — Helianthea ; 

 Hieracia ; Inulece and Ambrosiaceee likewise abundant among 

 the Composites ! — The next numerously represented families 

 are Onagreat ; Cactea, and Boraginea ! — Less numerous, yet 

 abundant in but few genera and species are, Crucifera, Tur- 

 neracece, Apocynea, Polemoniacece, Scrophularina, Pediculares, 

 Polygonea. — Rare are Eleagnece, Agrostidea, in the genera 

 Polypogon and Crypsis ! — Cyperoidea in divers species of 

 Carex .' — Labiata in the genera Monarda and Hedeoma ! — 

 Polemoniacece in Cantua ; Collomia ! — Rosacea in Rosa, 

 Purshia, and Potentilla ! — Turneraceee in Bartonia ! — Single 

 representatives ! — of Rubiacea, Galium septentrionale ! of 

 Papaveracea, Argemonef — of Fumariacea, Corydalis ! — Eu- 

 phorbiacea, Euphorbia! Liliacea, Calochortus, and of Ama- 

 ranthacea, Amaranthus nanus, Nuttail ! 



The peculiar characteristics of this Flora consist in the 

 perennial foliage of most of the shrubby Composite, and 

 the great number of succulents, chiefly Opuntia Missurica. 

 Annuals are very few, of rapid growth, early decay and incon- 

 spicuous ; with few exceptions ; consisting of humble Caryo- 

 phyllece, Polygonece, and Boraginece. Half the biennials 

 likewise decay in the early part of summer, as soon as 

 they have done blooming ; these are species of Townsendia, 

 CEnothera, Erysimum, jipargia, Cantua, &c. ; the other half 

 continue green, and even blooming, till late in the fall, as 

 different species of Hymenopappus, Cynoglossum, Bartonia, 

 Argemone, as well as a few annuals, (Cleorne, Castilleja, Col- 

 lomia). — The shrubby Composite flower late in September 



