§12 EXOGENOUS PLANTS. 
the Geum urbannum, of our gardens. In its geographical range it is pretty constantly associated with 
Pulsatilla patens, but is less common. Waldsteinia fragarioides, (Tratt.) Dividing ridge between the 
St. Croix and Bois Brulé Rivers. Potentilla Norvegica, (L.) July. Waste places. St. Croix. Poten- 
tilla paradoxa, (Nutt.) July. Sandy margins of Cornelian Lake, near St. Croix River. Potentilla 
Pennsylvanica, (L.) July 4th. Granite knolls near “ Little Rock,’ Upper St. Peter’s. Potentilla 
arguta, (Pursh.) June. A very common plant on the dry rolling prairies of Iowa and Minnesota. Poten- 
tilla anserina, (L.) July. Mississippi, above Fort Snelling. Potentilla tridentata, (Ait.) Shore of 
Lake Superior. Comarum palustre, (L.) July. Cranberry bogs, St. Croix. Fragaria Virginiana, 
(Ehrh.) Common strawberry. Fields and prairies, Iowa and Minnesota. Fragaria vesca, (L.) Wood 
strawberry. St. Croix. Rubus odoratus, (L.) Flowering Raspberry. South shore of Lake Superior. 
Rubus triflorus, (Richards.) May. Shady places. St. Croix. Rubus strigosus, (Michx.) Red rasp- 
berry. Falls of St. Croix. Not abundant, except in the vicinity of settlements. Rubus occidentalis, (L.) 
Black raspberry. St. Croix. Rubus villosus, (Ait.) High blackberry. Forming thickets. Falls of St. 
Croix. Rosa lucida, (Ehrh.) May. Dry soil. Iowa. Rosa blanda, (Ait.) May. Prairie rose. 
Iowa and Minnesota. Crataegus tomentosa, (L.) June. A fine shrub, distinguished for the profusion 
of its flowers and the beauty of its foliage. Banks of the Mississippi. Crategus coccinea, (L.) Variety 
mollis. May. Davenport, Iowa. Crataegus Crus-galli, (L.) June. Rock Island, Ill. Pyrus coronaria, 
(L.) April. Crab-apple.. Abundant on the banks of the Mississippi, near Davenport, Iowa, extending 
north to the St. Peter’s. Pyrus arbutifolia, (L.) Choke-berry. Bogs. St. Croix. Pyrus Americana, 
(D. C.) Mountain ash. Shores of Lake Superior. Amelanchier Canadensis, (Torr. and Gr.) April. 
This widely-spread and variable shrub seems to require a high northern latitude to perfect its fruit. In 
such situations it becomes an important article of diet, and forms a frequent ingredient in the Pemican, 
or pounded meat, so extensively used in those regions. The shrub is there known by the name of Pem- 
bina, which name has been applied to the Red River settlement of Lord Selkirk. 
LytHRaces.—Ammannia latifolia, (L.) August. Banks of Mississippi, near Des Moines Rapids. 
Lythrum alatum, (Pursh.) July. Margins of ponds. Iowa and Minnesota. Decodon verticillatum, 
(Ell.) Fish Trap Rapids, Upper St. Croix. 
OnaGrAcea.—Epilobium angustifolium, (L.) July. Waste places, St. Croix. Epilobium colora- 
tum, (Muhl.) July. Moist places. St. Croix. Epilobium palustre, (L.) July. Bogs. St. Croix. 
(Enothera biennis, (L.) Thickets, throughout the Northwest. (Enothera rhombipetala, (Nutt.) July 
21st. Sandy cliffs about Cornelian Lake. This species has only been found hitherto on the Arkansas 
and Missouri. Hnothera serrulata, (Nutt.) June. A characteristic plant of the gravelly ridges on the 
St. Peter’s, and in the interior of Iowa. Gaura biennis, (L.) August. Dry fields. Davenport, Iowa. 
Ludwigia palustris, (Ell.) Wet places. St. Croix. 
Circmacea.—Cirewa lutetiana, (L.) Moist woods. St. Croix. Cirewa alpina, (L.) Deep woods. 
Upper St. Croix. 
HatoraGe#.—Myriophyllum verticillatum, (L.) Floating in still ponds. Interior of Iowa. Hispuris 
vulgaris, (L.) July. Reedy swamps on the St. Peter’s, near Traverse des Sioux. 
Cactacra.—Opuntia vulgaris, (Mill.) July. Crevices of the bare granite rocks, Upper St. Peter’s, 
and at the Falls of the St. Croix. This species seems to be nearer to our common Prickly Pear than to 
the O. Missouriensis, which latter is referred to the Rocky Mountains, and the plains of the Missouri. 
GROssULACEE.—Ribes cynosbati, (L.) Prickly gooseberry. Rocky woods. Ribes Missouriense, 
(Nutt.) Borders of streams. Iowa. As far north as the St. Peter’s River. This characteristic species 
is to be noted for the luxuriance of its growth, and frequent abundance of its wild fruit. It is farther 
worthy of note, for affecting a dryer soil than is common to this class of plants; thus it would seem 
peculiarly fitting it for cultivation in the region of which it is a native. Ribes floridum, (L.) May. Wild 
Black Currant. Abundant on the alluvial bottoms of the Upper Mississippi. Ribes rubrum, (L.) 
Common Red Currant. Head of the Chippewa River. Mr. A. Randall. This common fruit-bearing 
shrub of our gardens was frequently observed growing wild by various members of the Geological corps, 
during the season of 1847, when they had the opportunity of ascertaining its identity in fruit, with the 
red currant of our gardens. 
Cucurpitace#.—Echinocystis lobata, (Torr. and Gray.) Alluvial river banks. St. Croix and St. 
CrasuLace®.—Penthorum sedoides, (L.) July. Wet places. St. Croix. 
