LAVENDER. 217 



are more pronounced than in the Dalmatian variety. 

 The calcium oxalate crystals differ also. Those of the 

 former are imperfect small agglomerations, whereas those 

 of the latter are large, quite perfect single or twin crystals. 



Adulteration with Hungarian or Russian daisy may with 

 difficulty be detected, by the presence of the trichomes 

 peculiar to the latter. These are long, three to ten- 

 celled, with a much inflated terminal cell. Other adul- 

 terants are numerous, among them the flowers of C. 

 Parthenium, C. tnodorum, C. corybosum, Leucanthemum cor- 

 onariunty Anthemis arvents, A. Cotiila, A. tinctoria and ^4. 

 nobilis, Inula pidicaria, Tanacetum vulgar e, Matricaria, 

 Calendula, are difficult to detect. Curcuma, sawdust, 

 and mustard are easily recognized, and chrome yellow, 

 barium chromate, and ochre are discovered in the ash, 

 which should not exceed 7 per cent. 



Chemistry. — The active insect-killing constituent has 

 not been determined. Volatile oil, resin, cholesterin, 

 a paraffin, a glycoside, an alkaloid, and three acids, one 

 volatile, have been found. 



LAVENDER. 



The unexpanded flower of Lavandula vera, De C. (nat. 

 ord. Labiatece), a plant of southern Europe; now exten- 

 sively cultivated. 



Description. — Bracts rhombic-ovate, pointed, brown- 

 ish and glandular; calyx tubular, about 5 mm. long, 

 hairy and glandular, blue-gray, thirteen-ribbed, five- 

 toothed; the upper tooth is more developed, darker 

 colored. The corolla is violet-blue, dries often . to a 

 brownish color; about 10 mm. long, on the outside 

 hairy and glandular; two-lipped, the upper lip has two 

 lobes, the lower lip is smaller and has three lobes ; stamens 

 four, didynamous, short, inserted on the corolla tube, not 

 extending out of the corolla tube. The corolla is tra- 

 versed by numerous vascular bundles, and is covered with 



