WEEDS OF THE MUSTARD PAMILl 



83 



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

 which attacks cabbage and turnips and all three should therefore 



«A£ 



be kept away from these Vi g 

 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 railway^. 

 The pods are 2— t inches long 

 and each one contains 120 or 



Fig. 49. TumbUng mustard; a, base of stem of annual more See ds. * Oil a single plant 

 plant; fc, one of the lower leaves; c, flower X VA', a, ox 



branch with flower and pod?. (After Dewey.) 12,500 pods Were Once COlinted. 



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 stool stems and with a long two-edged beak which is 

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

 of the black mustard. (Fig 50.) 



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

 counties. May-Sept. Occurs in meadows and grain fields, 8 



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 



