CORN MINT, BLUE BOTTLE. 



33 



one of the most natural possible, and well marked in habit 

 and character. The herbage is generally more or less hairy. 



The "Corn mint," or the "Mentha arvensis," has the flowers 

 whorled. Leaves ovate. Stem much branched, diffuse. 

 Calyx bell-shaped, clothed all over with horizontal hairs. 

 The stems are much branched. Leaves inclining to elliptical, 

 obtuse, pale, clothed with rather rigid prominent hairs. 

 Flower stalks shortish, round, generally smooth, sometimes 

 furnished with a few spreading or slightly defl^xed hairs. 

 Calyx shorter, more bell-shaped and more broadly toothed 

 than in any of the foregoing, and essentially characterised by 

 being clothed all over with horizontally spreading hairs. 

 Flowers reddish lilac, externally hairy. 



This plant grows abundantly in corn fields where water 

 stagnates in winter, especially on a sandy or gravelly soil. 

 It is often a very troublesome weed, because of the widely 

 creeping nature of the root, and its turgid fleshy shoots well 

 calculated to retain life in a soil that fluctuates as to humidity. 

 The roots being perennial, must be picked by hand, and 

 carried from the field, each time when the land is ploughed, 

 harrowed, and rolled. The roots are very tenacious of life, 

 and must be carefully removed. 



28. The " Blue bottle," or the " Centaurea" of botany, is 

 sometimes found as a weed on corn fields. The plant be- 

 longs to the class and order " Syngenesia polygamia frus- 

 tranea" of Linneus, and the natural order " Cinarocephalse" 

 of Jussieu. 



Generic character. — Calyx common, imbricated, roundish 

 scales variously terminated. Corolla : compound, floscular 

 florets, differing in form ; those of the disk hermaphrodite, 

 numerous; those of the ray fewer, loose, larger, funnel-shaped, 

 constantly abortive ; tube of the hermaphrodite florets filiform 

 border, bellying, oblong, erect, terminated by five linear erect 

 segments ; tube of the abortive florets slender, gradually en- 

 larging, recurved ; border oblong, oblique, unequally divided. 

 Stamens of the hermaphrodite florets : filaments five, capil- 

 lary very short ; anthers united into a hollow cylinder the 

 length of the petal; of the abortive florets, none. Pistil 



