610 EXOGENOUS PLANTS. 



parvifloruni, (Nutt.) July 1st. Crevices of the exposed granite and quartzite rocks, Upper St. Peter's 

 associated with Lycopodiuni rupestre and Woodsia Uvensis ; differing from the more common T. tereti- 

 folium, in the characters specified by Nuttall, but still doubtful as a distinct species. Claytonia Virgi- 

 nica, (L.) April. Rich hillsides. 



Malvaceae. — Abutilon Avicennas, (Gaertn.) July. Yards and roadsides, abundantly naturalized 

 about western towns. 



Linaceje. — Linum rigidum, (Pursh.) July. " Yellow flax." High prairies of Iowa. 



GrERANiACEiE. — Geranium maculatum, (L.) May. Copses and fields. Geranium Carolinianum, (L.) 

 May. Waste places, Iowa. Geranium Robertianuni, (L.) August. Shady crevices of trap-rocks, Falls 

 of St. Croix. 



Oxalidace^e. — Oxalis Acetosella, (L.) " Wood-sorrel." Rooting in moss, in deep woods, Lake Supe- 

 rior. Oxalis violacerc, (L.) May. Dry banks, Iowa. Oxalis stricta, (L.) Waste places. 



Balsaminaceje. — Impatiens pallida, (Nutt.). August. Springy places, St. Croix. Impatiens fulva, 

 (Nutt.) With the preceding. 



Zanthoxylace^e. — Zanthoxylum Amcricanum, (Mill.) April. " Prickly ash." Forming trouble- 

 some thickets on river-banks throughout the Northwest. Ptelia trifoliata, (L.) June. Dry river-banks. 

 Called " water-ash," from the singular appearance of its fruit. 



Anacardiace/E. — Rhus typhina, (L.) June. St. Croix. Rhus glabra, (L.) The most common 

 species of sumac. The milky juice from the fresh-cut branches affords an indelible ink. Rhus Toxico- 

 dendron, (L.) " Poison-ivy." Very abundant on all river-banks, thickets, &c. Rhus venenata, (D. C.) 

 " Poison-ash." Deep, swampy woods, St. Croix. Rhus aromatica, (Ait.) June. Sandy shore of Red 

 Cedar River, Iowa. 



AceracevE. — Acer spicatum, (Lam.) Upper St. Croix and Lake Superior. Acer saccharinum, (L.) 

 Interior of Iowa, Upper St. Croix, &c. Acer dasycarpum, (Ehr.) Alluvial river-bottoms throughout 

 the Northwest. Acer rubruin, (L.) Falls of St. Croix. Negundo aceroides, (Moench.) River-bottoms, 

 Iowa. 



Celastrace,e. — Staphylea trifolia, (L.) May. Thickets, Iowa. Celastrus scandens, (L.) This 

 common vine abundantly found in thickets, and along banks of streams, throughout the Northern States, 

 popularly known by the name of " Staff-tree," or " Climbing Bitter-sweet," is frequently resorted to by 

 the Indians of the Northwest, in times of scarcity, as an article of food. The vine itself, cut into pieces 

 of a convenient size, is boiled till the thick bark acquires a pulpy consistence, and the water becomes 

 impregnated with mucilage. The woody part being rejected, the rest is eaten. By the Chippewa In- 

 dians it is called Bi-ma-quat. Euonymus atropurpureus, (Jacq.) June. Blue Earth River, and banks 

 of the Mississippi. Showy in the frequent abundance of its scarlet fruit in winter. The root has also 

 attained note in some quarters as a medicinal agent. 



RHAMNACEiE. — Rhamnus alnifolius, (L'Hen.) May. Alder swamps of the St. Croix River. Rham- 

 nus longifolius, (Pursh.) Banks of the Mississippi, near Davenport, Iowa. Ceanothus Americanus, (L.) 

 July. " Red root." A shrubby plant, well known on the Iowa prairies as a troublesome obstacle, by 

 its tough roots in first breaking the soil. Ceanothus ovalis, (Bigelow.) May. Interior counties of 

 Iowa, and on dry sandy ridges of the St. Croix ; in the latter locality seeming to take the place of the 

 preceding species, and an indication of a more barren soil. 



Vitaceje. — Vitis riparia, (Michx.) " River-side Frost-grape :" the only northwestern species. Am- 

 pelopsis quinquefolia, (Michx.) June. River-banks. 



Polygalace^e. — Polygala purpurea, (Nutt.) July. Wet and rather barren places, Iowa and 

 Minnesota. Polygala incarnata, (L.) Dry soil, interior of Iowa. Polygala cruciata, (L.) July 28th. 

 Moist margins of swampy lakes, St. Croix. Polygala verticillata, (L.) Dry hills, Iowa. Polygala 

 senega, (L.) " Seneca snake-root." Polygala polygama, (Walt.) July. Sandy soil, St. Croix. Poly- 

 gala paucifolia, (Willd.) Long Portage Trail from Lake Superior to the Upper St. Croix. 



Leguminos^;. — Lathyrus maritimus, (Bigelow.) "Beach-pea." Common to the sandy shore of 

 Lake Superior, and the Atlantic sea-beach. Lathyrus venosus, (L.) June. Copses. St. Peter's. La- 

 thyrus ochroleucus, (Hook.) May. St. Croix and St. Peter's. Lathyrus palustris, (L.) Moist river- 

 banks, St. Peter's. Phaseolus diversifolius, (Pers.) August. " Wild bean." Gravelly banks of the 

 Mississippi, Davenport, Iowa. Apios tuberosa, (Moench.) August. The root of this common plant, 

 abundantly scattered on the banks of streams, and alluvial bottoms throughout the United States, is the 



