84 



'HE INDIANA WEED BOOK. 



rapidly and matures an immense number of seeds. Remedies : 

 clean seed; surface burning in fall or spring; hand pulling and 



cultivation of hoed crops; spraying 

 with iron sulphate (copperas) solu- 

 tion; harrowing stubble as soon as 

 crop is cut to start a rapid autumn 

 growth of the weed, then feeding oft' 

 with sheep ; harrowing young wheat 

 in autumn after it has a good start. 



45. Brassica nigra L. Black Mustard. 

 (A. I. 3.) 

 Erect, tall, 2-7 feet high, prickly with 

 short stiff hairs; lower leaves with a 

 large terminal and 2-4 smaller lateral 

 lobes. Flowers yellow. Pods erect, closely 

 appressed to stem, 4-sided, smooth, f inch 

 long, ending in a slender beak ; seeds dark 

 brown, very pungent, 1/25 of an inch 

 long, globular, finely pitted. (Fig. 51.) 



Fig. 50. (After Vassy. 



Common in fields and waste places. June-Nov. Remedies sam< 

 as for charlock. 



The seeds of both this and the 

 white mustard (Sinapis alba It.) when 

 ground are used extensively in medi- 

 cine for plasters, poultices, emetics, 

 etc. More than 5 million pounds are 

 imported each year, the price aver- 

 aging about 5 cents per pound. The 

 white mustard is a smaller plant, 1-2 

 feet high, flowers larger and paler yel- 

 low, the pods rough-hairy, with long, 

 flat sword-shaped beaks; seeds pale 

 yellow, smooth, larger and less pun- 

 gent than those of the black mustard. 

 In collecting the seeds for sale the 

 tops should be pulled when most of 

 the pods are ripe but before they be- 

 gin to burst open, placed on a clean 

 dry floor or shelf until fully ripe, 

 then shaken over a sheet or canvas. Fig. 51. (After Henkd.) 



40. Bursa buesa-PA.STOEIS 1a Shepherd's Purs*'. Mother's Heart. (A. I. 1.) 



Erect, branching, 6 20 inches high; lower leaves tufted, forming a 



rosette, out-lobed or toothed like those of the dandelion; stem leaves few, 



