=Canadian Erigeron= (_Erigeron canadensis_ L.), sporadic in England, is suspected in America. It contains an oil, chiefly a _terpene_ (C_{ 10}H_{ 16}). It has an acrid taste, causes smarting of the eyes, soreness of throat, aching of extremities, and colic; and irritation to people handling it (203).
=Mayweeds= (_Anthemis_ sp.). It is not at all clear whether these plants are more than irritant in character, and they are so very common and widely distributed that there would probably be more evidence if they were poisonous. _A. Cotula_ is regarded as suspected by Smith and Halsted, while Ewart says that it is obnoxious to stock on account of its unpleasant flavour, and if eaten by them in time of scarcity is apt to give their flesh, milk, or butter an unpleasant flavour. Güssow states that this species blisters the mouth and nostrils of animals. In his investigations at Kew, Greshoff found that the seeds of _A. Cotula_ and _A. arvensis_ contain much hydrocyanic acid. (He further found that the cyanogenetic glucoside from _A. aetnensis_ Schouw. and _A. chia_ L. belongs to the amygdalin type, giving off hydrocyanic acid and benzaldehyde on hydrolysis. “The strong odour of benzaldehyde may even be observed on grinding the seeds with water. Species of _Anthemis_ contained from 0·15 down to 0·03 per cent. of hydrocyanic acid.”)
=Cat’s-Ear= (_Hypochæris radicata_ L.). No record of poisoning of Cat’s Ear has been found, but it may be mentioned here, since Ewart says of it: “It contains a bitter, milky sap, which makes it unpalatable though not entirely poisonous.... An exclusive diet of this weed could not help but injure stock eventually.”
=Dodders= (_Cuscuta_ sp.), when parasitic on clovers and fed as fodder or hay, have been suspected of causing digestive troubles in horses and cattle in the United States. Müller records a case of poisoning of young pigs by _C. europæa_, with inflammation of the intestines and nervous symptoms. Barbey determined the presence of the glucoside _Cuscutin_ in _C. Epithymum_.
=Viper’s Bugloss= (_Echium vulgare_ L.) is suspected of being poisonous; according to Friedberger and Fröhner it causes slavering (see also _Cynoglossum_).
=Hound’s Tongue= (_Cynoglossum officinale_ L.). To what extent this plant is actually poisonous is not clear, but with some other members of the order (_Echium vulgare_, _Anchusa officinalis_), it contains the two alkaloids _Consolidine_ and _Cynoglossine_—the former of which paralyses the central nervous system and the latter the peripheral nerves. (Greimer, 1900: _vide_ Henry).