ARBORETUM AND FKUTICETUM. PAKT III. 



CHAP. XCII. 



OF THE HARDY LIGNEOUS TLANTS OF THE ORDER POLYGONA v CE^. 



DISTINCTIVE Characteristics. Leaves alternate. A filmy cylindrical 

 sheath, called an ochrea (which signifies a boot), arises from the base of every 

 leaf, except in three genera, and surrounds the stem or branch for more or less 

 of the interval between that leaf and the next above it. Generally speaking, 

 this is sufficient to distinguish the Polygonaceae from all other plants. Addi- 

 tionally, they have an erect ovule, with a superior radicle, and, in most, fari- 

 naceous albumen. (Lind/cy Nat. Syst.of Bot.) The hardy ligneous species 

 are included in the three genera, Tragopyrum Bicb., ./ftraphaxis L., and Cal- 

 Ifgomim L. ; which have the following characters. 



Tuagopv v rum Bicb. Calyx inferior, with 5 sepals, that are imbricate in 

 activation, permanent ; the 2 exterior smaller, the 3 interior investing the 

 fruit, which is an achenium that is 3-cornered in a transverse section of it. 

 Stamens 8. Styles 3. Undershrubs, with the habit of ftraphaxis, but 

 decumbent or trailing ; and the leaves of one of the species, at least (T. 

 /nixifolium Bicb.), are deciduous. In the stamens and pistil they resemble 

 Polygonum, and in the calyx Rumex. (Bicb. Fl. Taur-Cauc, iii. p. 284. ; 

 Lindlcy Nat. Syst. of Bot.; and observation.) Pedicels jointed in T. lanceo- 

 latum Bicb. and T. polygamum Spr. (Vent.) 

 Ituapha'xis L. Calyx inferior, of 4 leaves, in an outer smaller pair and an 

 interior pair, the latter resembling petals; or 4-parted, with the lobes equal. 

 Stamens 6. Stigmas 2, in one species ; style bifid, in the other. Fruit 

 compressed, in one species; roundish, in the other. Seed 1. — Species 2. 

 Small shrubs, with leaves more or less ovate. ( Willd. Sf). PL, 2. p. 248, 

 249., and obs.) 

 Calli'gonum L. Calyx inferior, persistent, turbinate in the lower part, 

 ending upwards in a 5-parted spreading border; the 2 outer lobes rather 

 the smaller. Stamens about 16; the filaments slightly united at the base, 

 and then diverging. Anthers peltate. Germen 4-sided, acuminate. Styles 

 4 or 3, united at the base for a little way, slender, spreading. Stigmas 

 capitate. Fruit an achenium that has 4 sides and 4 wings ; and the wings 

 are either membranous, longitudinally 2-parted, toothed, and curled, or 

 rough with branched bristles. C. Pallasw, the best-known species, is an 

 erect shrub 3 ft. or 4 ft. high, with rush-like shoots, without obvious leaves, 

 with the flowers in groups, and their calyxes partly white. (L'Heriticr in 

 Lin. Soc, Trans., i. p. 177. ; and Rccs's Cyclop.) 



Genus I. 



TKAGOPY'RUM Bicb. Thf, Goat Wheat. Lin. Syst. Octandria 



Trigynia. 



i,i, nfijtftifiou. Bicb Flor Taurico-Caucai., & p. 984. 



Polygonum Un. Hart. Ups., 95., mild. Sp., 2. p. 440., Bot. Mag., t.lQ55., Bot Reg 



, a goat, aiulpuros, wheat. The 3-oornered fruits of such of the Polygonaces 

 I them an comparable, with tome allowance, to wheat; and goats may feed upon those of 



rragoptrum, <,r upon the ihrubf tbemtelves ; or It may be that the name baa been invented 

 < readily distinctive from the name I'agopyrum, now the name of a genus that includes the 



different kinds of buck-wheat 



• r I. T. j, am BOLJ ii m Bieb* The lanceolate-ZcY^tv/ Goat Wheat. 



HcmtMIt hi ii BUbv FL Tanricc C aueai _ 



/'olyKonum frutcAcen, Willd Sp Pl.,2. p. 440., Willd. Banmx., p. 286., Bot Beg., 



chartiger Kntfterig, Oer. 



'.-,,. i si.,') t 12 f. 2 ; Bot, Reg., t. 254.; and enr fig in. 



