1382 • WEEDS AND PARASITIC FI.OWERIXG PLANTS 



WneEDS AND PARASITIC FLOWERING PLANTS. 



1040 - "Witch Weed" or " Rooi-Bloem" (Strig-a lutea), a Phanerogam parasitic 



on Maize in Rhodesia.— Walter J. a. T., in The Rhodesia A'^ncnltv.ral Journal, 

 Vol. XIII, No. 2, pp. 234-236. Salisbun', iqi6. 



The appearance of "witch weed" or " rooi bloem" [Striga lutea) has 

 been reported in the valley of Mazoe ; its occurrence is recognised b}' the 

 scarlet colour of the inflorescence and the reduction in the foliage. It 

 attaches its roots to those of maize and deprives its host of a considerable 

 quantity of sap, hindering its growth and sometimes preventing the forma- 

 tion of the ear. 



S. lutea spreads rapidly, and is capable of destro3dng within a short time, 

 throughout entire districts, the crop of maize, this being the only cultivated 

 plant which is the host of the j^arasite. In consequence of this fact control 

 experiments were carried out by means of appropriate rotations, but the 

 result of these trials was negative, owing to the persistence of the Striga seeds, 

 which are capable of retaining their vitality for many years in the soil. 



The only practical remedy is to pull up the Striga plants and destroy 

 them by fire as soon as they appear on the surface of the soil. 



10^1 - Khaki Weed {Alieinanthera Achyrantha) in Queensland. — Bailey j. f. 



and White C. T., in Queensland Ai^ricultural Jourmd, Xew Series, Vol. V, 5th Part, 

 pp. 277-278, Fis;. I. Brisbane, 1916. 



A description of the " Khaki weed " [Alternanthera achyrant/m R. 

 Br.). It was imported from Argentina to Africa in forage during the Boer 

 war. It was introduced into Australia, first invading New South Wales 

 and afterwards extending to Queensland. 



1042 - Cut-leaved Nightshade (So/anum triflorum Nut.) and London Rocket {Si- 

 symbrium Irio). New Weeds in New South Wales. — Hamilton a. a., in .4^^/- 



cultural Gazette of New South Wales, Vol. XX\'II, 4th Part, pp. 273-276. Syclne}-, 1916. 



" Cut-leaved nightshade " {Solanum triflorumNnt.) a solanaceous plant 

 reported in the district of Cooma. The berries and overground parts of 

 the plant, which contain solanine, are poisonous. 



" London Rocket " {Sisymbrium Irio Iv.) a crucifer met with in the envi- 

 rons of Cobar and N3mgan. The plant was probably introduced with 

 lucerne seeds. It has no injurious properties, but in view of the rapidit}' 

 and intensity with which it spreads in lucerne fields, replacing the crop, 

 S. Irio is regarded as a weed. 



1043 - Agrosiemma githago among Cereal Grains. Determining the Coefficient 



of Impurity. — .See Xo. ()66 of this Bulletin. 



