lo June, 191 2.] Weeds, Aliens, and Poison Plants. 359 



THE WEEDS, XATLIRALIZED ALIENS AND POISON 

 PLANTS OF VICTORIA. 



By Alfred J. Eivart, D.Sc, Ph.D., F.L.S., Government Botanist and 

 Professor of Botany and Plant Physiology in the Melbourne University. 



Watsinia Meriana, Mill. Var. Iridifolia (iridese). 



This plant, often known as Merian's Bugle Lily, is a native of South 

 Africa, which was first recorded as a permanent naturalized alien in 1907 

 (Victorian Naturalist, vol. 24, page 16). The plant is a rather handsome 

 ■one, and was cultivated in gardens long before this, thence spreading and 

 running wild, until in some parts it is quite a troublesome weed, particularly 

 in neglected pastures which are moist or somewhat swampy during a 

 portion of the year. It also shows a special predilection for growing 

 along the banks of small water-courses, even where these are dry for the 

 greater part of the year. Although it likes moisture, it is able lo remain 

 green over prolonged periods of dry weather, and at such times the green 

 colour appears sometimes to attract stock and lead to their eating the 

 plant, although it is surprising how little of it is usually eaten, in spite 

 of its externally attractive and succulent appearance. 



The plant is often reported as having exercLsed an injurious or poisonous 

 action upon stock, and since it belongs to an ordei which includes such 

 poison plants as the Cape Tulip {Homeria collina), as well as many which 

 are injurious without being strictly poisonous, all such cases are worthy 

 ■of critical experimental investigation. The Iris itself, for instance, con- 

 tains, particularly in the rhizome, a peculiar acrid oleo-resin, sometimes 

 known as Irisin, which, apparently, consists of a mixture of a bitter acrid 

 fixed oil or soft resin, a volatile crystallizable oil, and other extractives. 

 This oleo-resin of Iris appears to exercise an irritant action on the mucous 

 membrane of the alimentary canal, and, hence, acts as a purgative, as 

 well as a powerful stimulant to the liver. It also has emetic and diuretic 

 properties, such as are possessed by the extracts from many other plants 

 belonging to the same order. In the case of the Cape Tulip, it is pro- 

 bable that the plant contains a similar oleo-resin to that present in Iris, 

 but that it is either more intense in its action or more abundant. 



It is evident, therefore, that the reports as to Watsonia being poisonous 

 could not be dismissed without full investigation. Accordingly, Dr. 

 Rothera undertook to investigate the supposed poisonous character of this 

 plant, and his results are published in brief in the Journal for November, 

 1 9 10. He found that sheep, goats, and rabbits eat it readily, and that 

 no harmful after-effects were noticeable. He could detect no alkaloid 

 either in the bulbs or in the green parts, while injections of extracts 

 •designed to contain active principles if present, produced no apparent 

 poisonous action. One possibility still, how^ever, remained open. In 

 some cases, as, for instance, in the case of the Darling Pea {Szvainsona 

 ^alegi folia), a poisonous action may be exercised in the course of time by 

 plants from which it is exceedingly difficult or impossible to extract any 

 poisonous principle, and if such plants are only eaten for a short period 

 of time, no evil effects may result. In the case of the Swainsona, four 

 to six weeks are required to produce serious svmptoms, when the plant 

 is eaten in moderate amount mixed with other food, and the effects are 



