SCLEEANTHE^— KNAWEL TRIBE 99 



branc ; stem spreading ; annual. Although this plant is very frequent in 

 corn-iields, especially where the soil is of gravel, yet it is noticed by few save 

 the botanist. It is about two or three inches high, with nian}^ spreading 

 stems and awl-shaped leaves ; and it bears, from July to September, small 

 green flowers, which either grow in the forks of the stems, or form small 

 terminal clusters. The slender stems are light green, slightly downy, and 

 much l)ranched and entangled ; the leaves keeled, opposite, and united at the 

 base by a membranous fringed margin. The Swedes are said to allay the 

 tooth-ache by inhaling the steam from a decoction of this KnaAvel. It is very 

 conmion in Sweden, where it is called Tandgrds. The French term the 

 ]i\i\nt La Gnarelle aiiniieUe, and the Germans Der wilde KiKindJe ; while it is 

 known to the Dutch by the name of Jaarhjhjs hardblocm. The latter name 

 is very expressive, as, when in seed, the perianth becomes quite hardened. 

 This Knawel is common throughout Europe on sandy soils. It flowers in 

 July, and scatters its seeds abundantly during autumn. A number of young 

 plants shortly arise, many of which survive the winter ; while some of the 

 seeds do not vegetate till the spring following, at which season a fresh set of 

 young plants make their appearance. Both this and the next species often 

 occur on dry gravelly heath-lands. 



2. Perennial Knawel (*S'. percnnis).— Calyx of the fruit with blunt, 

 closed segments, edged with a broad white membrane ; stems prostrate, 

 either simple or irregularly branched ; perennial. This plant has pale green 

 stems, and its small greenish flowers expand from August to November, 

 having a variegated appearance from the broad white membrane at the edge. 

 The plant, though not rare, is not very generally distributed. It is not 

 infrequent on the open sandy downs of Norfolk and Suff"olk, and is very 

 abundant in the neighbourhood of Elvedon ; while in several countries of 

 Europe it is a very common flower. In some lands the roots are attacked 

 by the insect called the Scarlet-grain of Poland {Coccus polonicus). This 

 yields a very rich crimson tint, and on this account the plant was once 

 collected in large (juantities in the Ukraine, and in Lithuania, for dyeing red. 

 The Coccus is probably still in use for dyeing silk and hair in Turkey and 

 Armenia, as well as for colouring the nails of the women's fingers ; but it is 

 not now much used in Europe, except by the peasantry of Poland. A similar 

 insect, found on the roots of the burnet (Poterium sanguisorha), was formerly 

 collected by the Moors for dyeing silk and wool of a rose-colour ; but this, 

 as well as a Coccus foimd on the bearberry, is now neglected. The insect 

 feeding on the Perennial Knawel is said sometimes to attack the annual 

 species, and also to infest occasionally the roots of the silverweed (Potentilla 

 anserine). Sir J. E. Smith says that he never found the insect on any of 

 these plants in England. 



Order LXXI. POLYGONE^E— PERSICARIA TRIBE. 



Flowers often bearing stamens only, or pistils only ; perianth deeply 

 3—6 parted, frequently in two rows ; stamens 5 — 8 from the base of the 

 perianth ; ovary 1, not attached to the perianth ; styles 1 — 3 ; fruit a flattened 

 or triangular nut. This order consists of herbaceous, rarely shrubby plants, 



13—2 



