SPEAR THISTLE. FIELD THISTLE. 



21 



toothed at the mouth. Pistil: germ ovate; style filiform, 

 longer than the stamens ; stigma simple, subulate, naked, 

 emarginate. Pericarp none ; calyx converging a little. 

 Seeds solitary, obovate, four-cornered, the two opposite cor- 

 ners obliterated ; down sessile, very long. Receptacle hairy, 

 flat. 



Essential character. — Calyx ovate, imbricate with spiny 

 scales; receptacle hairy. 



The " Spear thistle," or " Carduus lanceolatus," is some- 

 times seen on corn fields, but more generally on ditch banks 

 and the sides of hedges. Leaves decurrent, pinnatifid, hispid; 

 divisions divaricate ; calyxes ovate, spiny, villose. Stem 

 hairy. Root biennial ; stem upright, three or four feet high, 

 angular, downy, and sea-green underneath ; hairy, and deep 

 green above. Flowers in July. It is often called the "bur- 

 thistle." The flowers have the property of curdling milk. 



The means of eradication are cutting and pulling the stem, 

 and using the most diligent attention that no seeds be per- 

 fected. If cut in the early season, side branches will shoot 

 and perfect seeds, so that a second cutting is required ; but, 

 if allowed to grow to height, one cutting will be sufiicient. 

 Every plant in lanes, road-sides, ditch-banks, and in the roots 

 of hedges, should be very carefully destroyed, for the seeds 

 are winged with dowm, and are easily carried by the wind to 

 distant places, where they aHght and grow. 



15. The " Field thistle," or " Carduus arvensis," is placed 

 in the second section of the species, having the leaves " not 

 decurrent." The leaves are sessile, pinnatifid, spinous-stem^ 

 panicled ; calyxes egg-shaped, slightly spinous, down 

 feathery. Root perennial, creeping, tapering, descending 

 deep into the ground,- not easily extirpated. Stems three 

 feet highj erect, round, smooth, many-flowered. Leaves 

 sHghtly decurrent, alternate, smoothish; lobes unequal, ciliated, 

 spinous. Flowers white ; calyx egg-shaped ; scales broad 

 lanceolate, pressed close ; woolly at the edges, with a short 

 spreading spine ; down deciduous ; root permanent. 



The permanent root remaining in the ground, and sending 

 up flowering stems in succession, is the chief tendency to be 



