396 BOTANY AND PHARMACOGNOSY. 



rounded or conical torus, which is about 12 mm. in diameter and 

 2 or 3 series of lanceolate, obtuse, involucral scales. The ray- 

 florets are pistillate, the corolla varying in length from i to 2 cm. 

 and having numerous delicate veins and 3 short, obtuse or rounded 

 teeth. The tubular flowers are perfect and about 6 mm. long. The 

 ovary is 5-ribbed and the pappus forms a short, toothed crown. 

 The odor is distinct and the taste bitter. 



Persian Insect Flowers are derived from C. roscnm and C. 

 Marshallii, growing in the Caucasus region, Armenia and North- 

 ern Persia. The he'ads are about the same size as those of C. 

 cinerariifolinm; the torus is dark brown; the involucral scales 

 and ray-florets are purplish-red; the ovary is lo-ribbed. 



Insect flowers contain from a trace to 0.5 per cent, of a vola- 

 tile oil, the Persian flowers containing the larger proportion, and 

 the amount decreasing with the maturing of the flowers. They 

 also contain two resins, varying from 4 to 7 per cent., the larger 

 amount being found in the Dalmatian flowers ; a small quantity 

 of a glucoside and a volatile acid. 



The principle toxic to insects is Pyrethron, an amber-yellow, 

 syrupy substance which is the ester of certain unidentified acids, 

 and on saponification yields the alcohol pyrethrol which crystal- 

 lizes in fine needles. The acids combined in the ester pyrethron 

 do not give crystalline salts. 



Wormwood or Absinthium consists of the dried leaves and 

 flowering tops of Artemisia Absinthiiun, a perennial, somewhat 

 woody, branching herb, indigenous to Europe and Northern 

 Africa, cultivated in New York, Michigan, Nebraska and Wis- 

 consin and naturalized in the United States from plants that have 

 escaped from cultivation. The leaves are grayish-green, gland- 

 ular-hairy, I- to 3-pinnately divided, the segments being obovate, 

 entire, or lobed ; the flowers are yellowish-green, the heads being 

 about 4 mm. broad and occurring in raceme-like panicles ; the 

 torus is hemispherical and the involucre consists of several series 

 of linear bracts, the inner being scale-like ; the florets are all 

 tubular, the outer ones sometimes being neutral. The herb is 

 aromatic and very bitter. 



The fresh drug contains about 0.5 per cent, of a volatile oil 

 which is of a dark green or blue color, has a bitter, persistent taste 



