COLTSFOOT 197 



0-236 per cent. (Fair and Wright). The herb should therefore be 

 collected when the fruit begins to form (compare p. 111). 



Uses. Fresh hemlock herb is used for the preparation of the 

 green extract and juices. These are administered as sedatives in 

 various spasmodic diseases, in asthma, whooping cough, and spasmodic 

 affections of the larynx. 



Adulterations. Several indigenous Umbelliferous plants have 

 been mistaken for hemlock, but the characters detailed above are 

 sufficient to ensure the identification of the latter. The f ollowing 

 may be particularly alluded to : 



Anthriscus sylvestris, Hoffmann, Wild Chervil. One of the 

 commonest Umbelliferous plants ; it has, in common with the other 

 less frequent species of the genus, hairy leaves by which it is easily 

 distinguished from hemlock (fig. 105, b). The involucels are not 

 directed outwards, and the fruit is elongated. 



Chcerophyllum temulum, Linne, Rough Chervil, also has hairy 

 leaves. 



Mthusa Cynapium, Linne, Fool's Parsley. The ultimate divisions 

 of the leaves terminate in short brownish points. The under surface 

 is dark green and glossy, and exhibits a more or less distinct network 

 of veinlets (fig. 105, c). The umbel has no general involucre, and the 

 bracts of the partial involucre are long and narrow. A transverse 

 section of the leaf-stalk examined under the microscope shows on the 

 upper surface a large central cell developed into a trichome. 



Oenanthe crocata, Linne, has tuberculated roots ; the juice of both 

 stem and roots turns yellow when exposed to the air ; very toxic. 



Cicuta virosa, Linne, has narrow lanceolate, acute, serrated^ leaf- 

 segments. 



COLTSFOOT 



(Herba Farfarae) 



Source, &c. The coltsfoot, Tussilago Far/am, Linne (N.O. Com- 

 positce), is a small herb with perennial creeping rhizome, abundant in 

 Great Britain. The leaves appear much later than the flowering stems, 

 and these two parts of the plant are therefore collected separately and 

 usually sold separately. They have been long used as a domestic 

 remedy for coughs. 



Description. The flowering stems, which appear in the early spring, 

 are about 15 cm. high, and bear numerous small, narrow, alternate, 

 reddish bracts ; they are simple and hairy, many of the hairs termin- 

 ating in dark, reddish brown glands. The flowerheads are terminal 

 and solitary and surrounded by reddish involucral bracts ; they 

 possess numerous ray-florets with short, very narrow, bright yellow 



