194 COMMON WEEDS 



grown on June 2oth with a 15 per cent solution 

 of sulphate of iron (60 Ib. in 40 gallons of water) 

 became quite black and were killed ; as gramineous 

 plants are but little damaged by such a solution, this 

 method might be tried where Dandelions are specially 

 plentiful. Experiment in both the United States and 

 Germany, also, has shown that a 5 per cent solution 

 of copper sulphate applied as a spray at the rate of 

 1 60 gallons per acre has largely destroyed the leaves 

 and flowering stems of Dandelions, preventing them 

 from seeding. A small plot should be treated at first 

 as an experiment to watch the effect under local con- 

 ditions. As regards lawns, &c., see p. 345. 



Mouse-ear Hawkweed (Hieracium Pilosella L.) is a 

 softly hairy perennial, with leafless stems about a foot 

 in height, solitary yellow flower-heads nearly i inch 

 across, oblong-lanceolate leaves 2 to 4 inches long, and 

 a stoloniferous or creeping rootstock. Flowering, May 

 to August. 



Orange Hawkweed (H. aurantiacum L.) resembles 

 the last species, but is larger, very hairy, and the 

 flowers are orange-red. It is a naturalised per- 

 ennial, propagated by both seed and creeping root- 

 stock. This is the Devil's Paint-brush of Canada, 

 where it is a " noxious " weed for the Dominion. 

 Flowering, June to August. 



Both of these weeds occur in dry pastures, and should 

 be cut down to prevent seeding, and the pasture im- 

 proved. It has been found in Canada that the Orange- 

 Hawkweed may be killed by broad-casting dry salt at 

 the rate of ij tons per acre. 



