44 
IOWA ACADEMY OF SCIENCE 
the other provinces east of the Rockies. It occurs in some of the irri- 
gated fields near Kamloops. 
Of the Dogbane Family {Apocynaceae) none of the species are especi- 
ally weedy in Manitoba and westward, though the Apocymim cannabinum 
is a most troublesome weed in Iowa and Minnesota. It is also a weed in 
the Rocky Mountain states. Of the Milkweed Family {Asclepiadacem) , 
The common Milkweed {Asclepias syriaca) occurs occasionally in south- 
ern Manitoba and less so in the Saskatchewan, though it is one of the 
most common weeds in Iowa and Minnesota. Of the family TJrticaceae, 
one weed is common from Kentucky north to Minnesota and Wisconsin 
and west to the Rockies ' and in the great basin country, namely the 
common Hemp {Cannabis sativa) which has largely spread from culti- 
vated fields of the plant and its use as a bird seed. The Nettles, especi- 
ally Urtica gracilis and JJ. dioica are common northward in Wisconsin and 
Minnesota, though not abundant in Iowa, found also in the Rocky Moun- 
tains in British Columbia and Manitoba. In the great basin, Salt Lake 
Valley, the western TJ. holosericea has taken its place. 
Of the family TJmhelliferae, I saw no introduced weeds, though doubt- 
less Pastinaca sativa and Daucus carota occur in Manitoba, both occur 
in British Columbia and in Washington. Both of these are common 
roadside weeds in the northern Mississippi Valley and eastward. The 
Wild Carrot is abundant in clover fields in the east.. It is disseminated 
with clover seed. The Cicnta macidata is common in Saskatchewan and 
Manitoba. 
Of the '}^ialvaceae one weed is fairly common in southern ^Manitoba, 
Common Cheeses {Malva rotnndif olia) . It is likewise common on the 
Pacific coast in Washington and British Columbia. A second species 
M. crispa is local in the Northern Mississippi Valley. The Evening 
Primrose {Oenothera biennis) of the Primrose Family Onagraceae, in 
its various forms is common on the Pacific coast, AA^ashington and British 
Columbia and more or less common in Saskatchewan and parts 
of Manitoba. The Fireweed {Epilobium angusti folium) is common 
everywhere in the Rockies and easily takes the front rank as a weed in 
the forest clearing in British Columbia and Washington. 
Comparatively few of the Labiatae are troublesome weeds in Canada ; 
Self-heal {Prunella mdgaris) is common on the Pacific coast and in the 
wooded districts of eastern Manitoba, elsewhere it is not common and 
occurs from Missouri to Minnesota. Occasionally one sees Teucrium 
canadense in southern Manitoba common from Missouri to Minnesota 
and Nebraska. On the west slope of the Rockies to the Pacific coast a 
