THE WEEDS OF NEW SOUTH WALES. 



Wattles (Acacia) are perhaps our principal plants which have been proved 

 to be poisonous, but only a very few of them. Mr. W. L. Hindmarsh in 

 recently sending me twigs of the Blackwood (Acacia melanoxylon) from the 

 Lismore district, says that the bark and twigs have been used by the blacks 

 to stupefy fish, and the twigs are suspected of poisoning pigs. An old refer- 

 ence in my Forest Flora, vol. i, p. 107, that the bark contains some Doison, 

 may be thus explained. 



There is a paper on " The Toxic action of Saponin " in the Philippine 

 Journal of Science, vol. i, pp. 1037-1042, by E. F. Bacon and H. T. Marshall. 

 It takes the physiological standpoint and will be found interesting, especi- 

 ally, as so little has been written on this somewhat obscure subject. 



The Corn Cockle (Agrostemma Githago) is an ornamental weed from 

 Europe, which I am sorry to say has been increasingly invading our wheat- 

 field's during the last few years. Its seed is undoubtedly poisonous owing 

 to the presence of a Saponin. It is the more dangerous because it is difficult 

 to screen from wheat. It poisons fowls and renders flour poisonous, though, 

 on account of its dark colour, it is not to be found in flours of high grade. 

 It belongs to the Pink family (Caryopliyllacece), a usually non-poisonous 

 family of plants, and its poisonous character may give a clue to the state- 

 ment that in America the seeds of one of the Chickweeds (Stellaria media) 

 are said to injure lambs when eaten in large quantities. 



(ii) Cyanogenetic Plants. 



By this term we mean plants which contain a certain principle called a 

 glucoside which, acted upon by a ferment in the plant, liberates hydro- 

 cyanic or prussic acid, a very poisonous substance. 



In this connection read a paper on the "Variegated Thistle (Carduus 

 marianus) as a Poison-plant," by Max Henry in the Agricultural Gazette 

 for September, 1912, p. 807. 



One or two of the Sundews (Drosera) so common in Australia in damp 

 places, have been reported as poisonous to cattle. A few years ago some 

 species were found to contain hydrocyanic acid, and this may be the key to 

 the matter. 



Oleander (Nerifiim Oleander). The prunings of this beautiful small tree 

 are dangerous. Stock will rarely nibble the tree, but will eat the wilted 

 prunings thrown over the fence. See the Agricultural Gazette for June, 

 1904, p. 544. Let me say that the practice of throwing garden prunings into 

 the paddock in which are the horse and cow, may be a dangerous one. It 

 may, of course, be instructive if it be noted whether the prunings are toxic T 

 before or after wilting. But people do not, as a rule, make physiological 

 experiments on their animals. 



For a case of a grass being poisonous at a stage of its growth, see " A 

 Blue Couch Grass (Cynodon incomplete Nees), which is sometime^ 

 Poisonous." Agricultural Gazette, 1912, p. 295. Dr. Petrie has chown that 

 at certain seasons it contains hydrocyanic acid. 



See also a paper, " The poisonous action of Johnson grass (Andropogon 

 Sorghum)," by A. C. Crawford, in Bull. U.S. Dept. Agric. Bureau Plant 

 Ind. 90, p. 31r-34. Mr. F. B. Guthrie has also found hydrocyanic acid in this 

 grass. See his article on "Sorghum Poisoning" in the Agricultural Gazette, 

 Sept., 1912, p. 812. 



