290 DIADELPHIA DECANDEIA. [cL. XVII. 



torn; wings inversely egg-shaped, coming together above, 

 shorter ; keel compressed, half-moon shaped, shorter than the 

 wings. Filaments ten, nine united, the uppermost separated, 

 flattish ; anthers small, roundish. Germen oblong, compressed. 

 Style triangular, membranous at the edges, ascending ; stigma 

 longitudinal, downy, united to the upper angle of the keel. Le- 

 gume large, oblong, somewhat compressed, pointed, one-celled, 

 one-valved. Seeds globular. Name from the Celtic pis, a pea. 



352. 

 1. P. maritimum. Sea-pea. Leaf-stalks flattish. above ; stem 



angular ; stipules arrow-shaped ; stalks many-flowered. Stems 



procumbent, four-cornered : leaves alternate, sessile, alternately 

 pinnate with a branched tendril : flowers purple, veined with crim- 

 son. Perennial : flowers in July . grows on stony beaches in se- 

 veral parts of the eastern and southern shores of England, and in 

 Shetland. Eng. Bot. vol. xv. pi. 1046. Eng. Fl vol. iii. p. 270. 



1036. 

 8. O'ROBUS. BITTER-VETCH. 



Calyx superior, cup-shaped, unequal, with five acute seg- 

 ments, the two upper shorter and more distant, the lower one 

 longest. Corolla of five petals ; standard inversely heart- 

 shaped, reflected at the sides, rather longer than the rest; 

 wings inversely egg-shaped, ascending, approaching each other ; 

 keel rounded, pointed, of two united petals, with separate 

 claws. Filaments ten, nine united into a compressed tube, the 

 other hair-like ; anthers small, roundish. Germen oblong, com- 

 pressed. Style thread-shaped, straight, ascending, channelled 

 above ; stigma longitudinal, linear, downy, extending along 

 the upper side of the upper half of the style. Legume oblong 

 or linear, somewhat cylindrical, pointed, ascending at the end, 

 one-celled, two-valved. Seeds several, roundish. Name from 

 o?'o, to strengthen, and bous, an ox. 353. 



1. O, tuber 6sus. Heath-pea. Common Bitter -vetch. Leaves pin- 

 nate with elliptical leaflets ; stipules half arrow-shaped, toothed 



at the base ; stem erect, simple. Root knobbed, creeping : 



stems about a foot high : flowers in long-stalked, axillar clusters, 

 variegated with blue, purple, and crimson. The root, which is 

 sweetish and astringent, is chewed by the Highlanders. Peren- 

 nial : flowers in June and July : grows in heaths, and in woods 

 and open pastures: common. Eng. Bot. vol. xvii. pi. 1153. Eng. 

 FL vol. iii. p. 272. 1037. 



2. O. niger. Black Bitter-vetch. Leaves pinnate with broadly 

 oblong leaflets ; stipules narrow lance-shaped, acute ; stems 



branched, erect, angular. Root creeping, woody : stems from 



one to two feet long : petals purple, variegated. Whole plant 

 turns black in drying ; hence its name. Perennial : flowers in 

 June and July : found by Mr. T, Drummond, in the Den of Airly, 

 Forfarshire ; and by Dr. Maclachlan, near Moy House, Inverness- 

 shire. Eng. FL vol. iii. p. 270. 1038. 



3. O. sylvdticus. Wood Bitter-vetch. Stems spreading, hairy, 

 branched, leaves pinnate, with numerous lance-shaped leaflets. 



Root creeping, woody : stems numerous, from one to two feet 



long : petals cream- coloured, streaked and tipped with purple. 



