276 



EXPERIMENTAL FARMS. 



pod is inclosed in a five-angled calyx which enlarges with it. "When the seeds are ripe 

 the apex of the pod opens, forming a four-toothed orifice. Each of the pods with its 

 enveloping five-winged calyx, measures about ^ inch in diameter, and contains an aver- 

 age of 16 round, black, slightly roughened seeds. This plants together with the 

 Tumbling Mustard {Sisymbrium altissimum, L. ;=:the S. sinapistrum, Crantz, of former 

 reports), Ball 'S[nsUxYd{N'edia paniculata, Desv.), Hare's-ear Mustard {Erysimum orientale, 

 R. Br.*), and False Flax {Camelina saliva, Fries.), has spread with almost incredible 



Fig. 18.— Cow Cockle. 



rapidity through the wheat-growing districts of Manitoba and the North-west Terri- 

 tories. The indications are that all of these were introduced from Europe in flax seed, 

 and, althougii in the case of the Cow Cockle and Ball Mustard, there was little in their 

 appearance from which it might been anticipated that they would become troublesome, 

 the rapidity with which they have spread shows how important it is that every one of 

 these plants should be destroyed by hand pulling or summer fallowing as soon as detected 

 on land in a new locality. 



*This plant is now known under the name of Conringia orientalis (L.), Andrz. 

 different genus from Erysimum and certainly should be separated from it.— J. F. 



Conringia is quite a 



