YARROW 683 



a 1- or 2-celled stalk, and a glandular summit consisting of 4 to 8 

 cells; pollen grains spheroidal, about 0.030 mm. in diameter, nearly 

 smooth, and having 3 pores; calcium oxalate in rosette aggregates 

 about 0.010 mm. in diameter; tracheae either spiral or having 

 simple pores, associated with slightly thickened, lignified, porous 

 libriform. 



Constituents. 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, per- 

 sistent taste but not the pleasant odor of the plant, and consists of 

 d-thumone (absinthol), thujyl alcohol, free and combined with 

 acetic, isovalerianic and palmitic acids, phellandrene and cadinene. 

 The other constituents of the drug include a bitter glucosidal prin- 

 ciple, absinthiin, which forms white prisms and yields on hydrolysis 

 a volatile oil; a resin; starch; tannin; succinic acid, potassium suc- 

 cinate, and about 7 per cent of ash. 



ACHILLEA. Yarrow or Milfoil. The leaves and flowering tops 

 of Achillea Millefolium (Fam. Compositse), a common roadside 

 weed (Fig. 301), naturalized from Europe and Asia, and contains 

 about 0.1 per cent of a dark blue volatile oil with a strongly aromatic 

 odor and a small amount of a bitter alkaloid, achilleine. The roots 

 of yarrow, on the other hand, yield a volatile oil with a valerian-like 

 odor. 



ACHILLEA NOBILIS of Europe contains an oil resembling that of 

 yarrow, but it is of finer quality and has a spice-like taste. Achillea 

 inoschata, an alpine plant of Europe, yields three alkaloids and a 

 volatile oil containing cineol, and is used in Italy in the preparation 

 of the liquor, "Esprit d'lva." Achillea tanacetifolia yields a blue 

 volatile oil having the odor of tansy. 



TANACETUM. Tansy. The leaves and flowering tops of Tana- 

 cetum vulgare (Fam. Compositse), a perennial aromatic herb (Fig. 

 302), indigenous to Europe, extensively cultivated and naturalized 

 in the United States. The leaves are large and pinnately divided, 

 and the flowers, both tubular and ligulate, are yellow, the heads being 

 in terminal corymbs. 



The powder is yellowish-green; non-glandular hairs few, 4- to 

 5-celled, about 0.150 mm. in length, the individual cells being some- 

 what oblong and with yellowish-brown contents; glandular hairs 

 on achenes with short stalk and large, ellipsoidal head; involucral 

 bracts with a row of transparent marginal cells and central portion 

 with narrow, thick-walled, libriform cells having numerous simple 

 pores; pollen grains spheroidal, thick-walled and with numerous 

 spinose, centrifugal projections; narrow trachese having scalariform 



