IOWA ACADEMY OP SCIENCE 
41 
tion'witli clover seed. The Hare’s Ear Mustard {Conringia orientalis) 
of grain fields is a recent introduction. The Horseradish {Badicula 
Arnwracia) , Marsh Cress {Badicula palustris) and Winter Cress {Bar- 
harea vulgaris) have long been known as troublesome weeds of the north. 
The Common Hedge Mustard {S. officinale) is not common in the prov- 
ince east of the Rockies though common in Iowa, Wisconsin and Minne- 
sota. It is much more common on the Pacific coast from Seattle to 
Victoria, Vancouver east to Sicamous Junction and Revelstoke. Several 
native species occur in eastern provinces, like 8 . ciimmnnis and ,8. 
incismiy the latter a mountain species. These along with the False 
Flax {Camelina saliva) make up the more important weeds of this 
family. The Camelina occasionally^ occurs in Iowa and is frequently 
found in Minnesota. Of the family Gapparidaceae, only one species 
occurs in the Canadian region, namely Gleome integrifolia. Introduced 
near St. Paul and other parts of eastern Minnesota and occasionally in 
Central Iowa. Indigenous to Western Iowa and abundant in Nebraska 
westward through Colorado, Utah and Nevada and north to eastern 
Washington and east to the Dakotas. It is fairly common in Saskatch- 
ewan and Alberta, less frequent in Manitoba. It is rare in British Co- 
lumbia except the more arid portions about Kamloops and Ashcroft. 
The only common weed of the Convolvidaceae in Manitoba is the 
]\Iorning Glory {C onvolvidus sepium) extending west to Moose Jaw. 
It is most frequent about Emerson, Manitoba, Pembina, North Dakota, 
and St. Vincent along the Red River ; frequent in Minnesota, Wisconsin, 
Iowa, Illinois, Nebraska, Kansas and Missouri and eastward. The Euro- 
pean Bindweed {Convolvulus arvensis) of Europe long known as a 
troublesome weed in the east and on the pacific Coast, widely scattered 
as an ornamental plant and has become a troublesome weed in Missouri 
and here and there in Iowa, does not occur in Manitoba or westward to 
the Rockies, but again on the Pacific coast from Vancouver to Oregon. 
In the south a number of species of Morning Glory are troublesome like 
the common Morning Glory {Ipomoea purpurea) and the 'white and 
purple or pale blue flowered annual Morning Glory (/. hederacea) com- 
mon in corn fields and springing up abundantly after the grain is cut. The 
perennial Man-of-the-Earth {I. pandurata) with fiddle-shaped leaves and 
white flowers is occasionally troublesome in corn fields. Mention should 
be made of the Dodders {Cuscuta) . The Flax Dodder (0. Epilinum) 
in the northwest, the Field Dodder {C. arvensis) on clover in Iowa, 
Wisconsin and eastward, and the Clover Dodder in the alfalfa growing 
sections of the west. The common Mullein {Verhascum Thapsus) is 
common in Minnesota and Iowa, although certainly not common in Mani- 
