WEEDS OF THE MUSTARD FAMILY. 



63 



well as the next two species, are hosts for the "club-root fungus" 

 which attacks cabbage and turnips and all three should therefore 



be kept away from these vege- 

 tables. 



Differing in having cream 

 colored flowers and much longer, 

 widely spreading pods is a 

 closely allied species, the tum- 

 bling mustard (S. altissimum 

 h., Fig. 49), a European plant 

 which is a bad weed in the 

 grain fields of Canada and the 

 Northwestern States. In Indi- 

 ana it has been recorded from 

 six counties and will doubtless 

 be found to be frequent in the 

 northern portion, especially 

 along the trunk line railways. 

 The pods are 2-4 inches long 

 and each one contains 120 or 

 w"x° f iKn! more seeds - 0n a single plant 



branch With flower and pods. (After' Dewey.) " ' 12,500 pods Were Once Counted, 



so that that plant alone produced 1,500,000 seeds. When the seeds 

 are ripe the whole head of the plant breaks off and, as a tumble- 

 weed, it may in winter be blown for miles, scattering a few seeds 

 in many places. It is liable to be introduced anywhere in baled 

 hay, and is especially liable to be found about elevators and railway 

 yards. Isolated plants should be pulled- before the seeds ripen. If 

 in numbers they should be mowed or cut with hoe in June and 

 again in August. 



44. Brassica arvensis L. Charlock. Wild Mustard. (A. I. 1.) 



Erect, branching above, 1-2 feet high; rough with scattered stiff 

 hairs; lower leaves stalked, cut-lobed; upper ones mostly sessile, feebly 

 notched or entire. Flowers yellow, fragrant. Pods long, cylindrical, 

 knotty, borne on stout stems and with a long two-edged beak which is 

 empty or 1-seeded ; seeds 15 or more in a pod, spherical, larger than those 

 of tbe black mustard. (Fig 50.) 



Frequent in the southern half of State, less so in northern 

 counties. May-Sept. Occurs in meadows and grain fields, espe- 

 cially those of oats, the seeds remaining with them when threshed. 

 The seeds have great vitality, often remaining buried for years or 

 until conditions are right for successful growth. It grows very 



Fig. 49. Tumbling mustard; , 



plant; 6, one of the lower leaves; c, flower X IK 



