CLASS VI. ORDER!.] JONCDS. 503 



as by the segments of the perianth being more acu e, and always ter- 

 minated in a bristle-shaped point, mostly of a pale colour. 



13. J. lampo'carpus, Ehrh. (Fig. 572.) Shining fruited jointed 

 Rush. Stem and leaves slightly compressed ; leaves apparently 

 jointed ; panicle compound, erect or spreading; segments of the peri- 

 anth equal, bristle-pointed, the three outer ones acute, the three inner 

 obtuse, shorter than three angled oblong lanceolate acute dark glossy 

 capsule. 



English Botany, t. 2143. English Flora, vol. ii. p. 175. Hooker, 

 British Flora, vol. i. p. 165. Liudley, Synopsis, p. 275. J.articulatus, 

 I-inn. van a. . 



/3. nigri' tellus, (Fig. 573 ) Panicle twice or thrice forked, with a few 

 heads of numerous flowers. J. polycephalus, D. Don. Hook. Flora 

 Scot. vol. i. p. 110. English Flora, vol. ii. p. 177. /. nigritellus, D. 

 Don. English Botany, Suppl. t. 2643. Koch. Flor. Germ. Helvet. 

 p. 730. 



y. re'pens, (Fig. 574.) Stem decumbent and rooting. 



S.fluit'ans. Stem elongating, floating, and rooting; var. . fiuitans, 

 Koch. 



Roots of long branched simple or downy fibres, and creeping under- 

 ground stems. Stems erect, or decumbent, as in y., putting out roots 

 from the joints, and becoming erect, or elongated, and floating upon 

 the surface of water, and putting out roots from the joints, as in J., 

 somewhat compressed, quite smooth, and leafy. Leaves slightly com- 

 pressed, rather short, tapering, slender, and not unfrequently long and 

 stout, smooth, hollow, with transverse partitions, giving it a jointed or 

 knotted appearance, dilated at the base into rather long thin sheaths, 

 with a membranous margin and short obtuse liyula, the panicle ter- 

 minal, compound, mostly forked and spreading; in 0. nigritellus 

 it is less branched, and with a few heads of numerous crowded 

 flowers, but commonly there are numerous heads of about six 

 flowers, each division of the panicle having a lanceolate bractea at 

 the base, s well as each of the sessile flowers. Perianth of six equal 

 oblong lanceolate pieces, each terminated with a small bristly point, 

 the three outer ones with a broad green obtuse keel, the three inner 

 with three ribs, and obtuse near the point, with a pale thin membranous 

 margin. Stamens about half as long as the perianth. Filaments 

 slender, and the anthers elliptical, yellow, erect. Style short. Stig- 

 mas long, spreading. Capsule about one-third longer than the perianth, 

 large, acutely triangular, oblong, lanceolate, with an acute point, of a 

 dark purplish brown colour, highly polished, opening with three valves 

 three celled, and bearing numerous small ovate seeds. 



Habitat. Watery meadows and boggy places ; frequent 



Perennial ; flowering in July and August. 



This is an extremely variable species, seemingly affected by the 



