50 THE WEEDS OF NEW SOUTH WALES. 



Mexican Poppy (Argemone mexicana I.). 



(PAPAYERACE^E : Poppy Family.) 



Other Names. For obvious reasons it often goes under the name of 

 "Prickly Poppy." It is also called "Blue Thistle" and "White Thistle," 

 because of the blueness or whiteness (whichever you like botanists call it 

 glaucousness) of its foliage. Sometimes it is called " Yellow Poppy." It is- 

 also sometimes known as " Binneguy Thistle," because it was so abundant 

 at Binneguy, near Moree, attention being drawn to it in the press from that 

 locality. 



[Articles and notes on this weed appeared in the Agricultural Gazette 

 for 1891, p. 175; 1895, p. 227; 1899, p. 490.] 



Botanical Description. 



A rather tall, glaucous, prickly herb, with yellow juice ; leaves sessile, deeply 

 sinuated, lobed, the lobes irregularly prickly toothed. Flowers yellow, large. 

 Capsules obovate, prickly. 



Is it poisonous? It belongs to the Poppy family, the best known member 

 of which yields opium, which consists of the dried juice of the scratched 

 fruits. 



A Russian chemist found in the seeds' of the Mexican Poppy an alkaloid 

 which gives reactions similar to morphia, a substance which is, of course,, 

 obtained from opium. The Pharmaceutical Review of October, 1901, p. 

 458, contains a paper, "Does Argemone mexicana contain morphine?" a 

 paper I have not been able to consult. 



Mr. C. J. Salter, of the Dubbo district, to be quoted presently, says that 

 sheep " would not even touch the Mexican Poppy." Further on, he says that 

 horses would not touch a single leaf of the Mexican Poppy. At the same 

 time he says that some chaff with some Mexican Poppy in it griped his 

 horses. 



In the year 1907, when on a visit to Aberdeen to inquire into the deaths 

 of cattle and horses supposed to have been caused by poison-plants, my atten- 

 tion was especially drawn to Mexican Poppy, which was very abundant. I 

 could not, however, see any sign of a plant being nibbled, and no one in the 

 district had ever heard of nibbling. Published inquiries prior to and sub- 

 sequent to 1907 have never elicited any case in which stock ate the plant. 

 It seems to me that the plant contains something especially distasteful to 

 them. 



Mr. Salter's experiment should be repeated by a Stock Institute, ior I do- 

 not understand it. It may be that other plants got mixed with the chaff as 

 well as the Mexican Poppy. Further, and I am a layman in veterinary 

 matters, I should have thought that Mexican Poppy, containing an active 

 principle which is a sedative, would not cause " violent fits of gripes." At 

 the same time, it is quite possible that, in addition to the alkaloid akin to 

 morphia, there may be an active principle which would gripe. 



How to get rid of it. The method is simple on paper hoe it out when it 

 is in flower; but in practice this often cannot be done, because of the great 

 hold it has secured, often in fissures, into which it has been washed with a 

 quantity of nice silt by successive floods, so that the young seedlings have 

 every chance. 



