CRUDE DRUGS. 555 



Description. Globular, compressed, 1.5 to 2 cm. in diameter; 

 involucre hemispherical, with two or three rows of imbricated, 

 nearly equal, somewhat elliptical, very pubescent scales, having a 

 greenish middle portion and a yellowish margin ; torus conical or 

 convex, solid, 3 to 4 mm. high, occasionally hollow, and some- 

 times containing the larvae of an insect ; chaff-scales resembling 

 the involucral scales, about 2 mm. long; ligulate florets numerous, 

 6 to 10 mm. long, corolla white, 3-toothed, 4-nerved, ovary about 

 I mm. long, glandular, style slender, stigma bi-cleft ; tubular 

 florets few or none, lemon-yellow, perfect; akene oblong, pappus 

 none ; odor distinct ; taste aromatic and bitter. 



Constituents. Volatile oil, which is bluish-green when 

 fresh, 0.8 to i per cent. ; a bitter crystalline glucoside anthemic 

 acid (see Matricaria) ; 5.25 per cent, of resin; 1.50 per cent, of 

 a bitter crystalline wax ; and tannin. The volatile oil consists 

 principally of the isobutyl, amyl and hexyl esters of butyric, 

 angelic and tiglic acids, and anthemol, an isomer of camphor. 



CALENDULA. MARIGOLD. The ligulate florets of Cal- 

 endula officinalis (Earn. Compositse), an annual herb indigenous 

 to Southern Europe and the Levant, and widely cultivated as a 

 garden plant. The flowers are collected when fully expanded, 

 and dried (p. 394). 



Description. Florets usually without the ovary ; corolla 

 bright yellow, 15 to 25 mm. long, i- to 3-toothed, 4- or 5-veined, 

 margin nearly entire, tube sometimes inclosing the remains of a 

 filiform style and bifid stigma, pubescent on the outer surface ; 

 ovary oblong, about 0.5 mm. long, pubescent ; odor distinct ; taste 

 faintly saline, slightly bitter. 



Constituents. Volatile oil ; an amorphous bitter principle ; 

 a gummy substance, calendulin, which forms with water a trans- 

 parent mucilage that is not precipitated by tannin ; and resin. 



Allied Plants. The florets of various Compositse are some- 

 times admixed with or substituted for Calendula, of which the 

 following may be mentioned together with their principal dis- 

 tinguishing characteristics : The ligulate corolla of Taraxacum 

 officinale is 5-toothed ; the ligulate corolla of Arnica niontana is 

 7- to i2-veined; the ligulate corolla of Tussilago Far far a is linear, 

 about 13 mm. long and about 0.3 mm. broad, apex acute, entire; 



