POLYGONACEAE (BUCKWHEAT FAMILY^ 361 



times lanceolate, obtuse or acutish, rounded or rarely subcordate at the base 

 (5-12 cm. long); peduncles glabrous: spike terminal, dense, ovoid or short- 

 cylindric (1.2-2.4 cm. long); flowers bright rose-color, 3-6 mm. long ; the 5 sta- 

 mens and 2-cleft style exserted. Lakes and pools, e. Que. to N. J., and westw. ; 

 widely distributed and rather common. (Eurasia.) Var. TERRESTRE Leers is 

 an erect terrestrial state with narrower acutish shortly petioled leaves scabrous 

 on the margin and often strigose-pubescent ; sheaths without herbaceous bor- 

 der. Occasional with the typical form (also Eu.), and passing in Am. to Var. 

 HARTWRIGHTII (Gray) Bissell with spreading foliaceous borders on the stipular 

 sheaths. (P. Hartwrightii Gray. ) An ambiguous plant, sometimes clearly a 

 mere terrestrial and mostly sterile state occurring on the same rootstock as the 

 typical form ; but elsewhere seemingly a normal and well marked fertile variety. 



15. P. MuhlenbSrgii (Meisn.) Wats. Perennial, in muddy or dry places, 

 rarely in shallow water, decumbent or suberect, scabrous with short appressed 

 hairs ; leaves lanceolate to ovate, narrowly acuminate (1-2 dm. long) ; peduncles 

 hispid and often glandular; spikes 3-10 cm. long, often in pairs; flowers and 

 fruit nearly as in the last. (P. emersum Britton.) Que. and Me. to Fla., and 

 westw. Exceedingly variable in foliage and pubescence ; aquatic states often 

 have essentially glabrous and cordate leaves, while in plants of drier situations 

 these are sometimes narrowly lanceolate, acute at base, and conspicuously ap- 

 pressed-pubescent on both surfaces. 



16. P. pennsylvanicum L. Annual ; leaves lanceolate ; branches above and 

 especially the peduncles beset with stipitate glands ; flowers uniform, bright 

 rose-color, in short erect spikes, often on exserted pedicels; stamens usually 8; 

 acliene nearly orbicular, over 2 mm. broad, at least one surf ace concave. Moist 

 soil, in open waste places, centr. Me., westw. and south w. Neither the stamens 

 nor style conspicuously exserted. 



17. P. longistylum Small. Very like the preceding in habit and foliage; 

 flowers dimorphous, either the stamens or style conspicuously exserted ; achenes 

 orbicular, shining, both surfaces convex in the middle. From s. 111. and Mo. to 

 w. Kan. (Meehan), and south w. 



18. P. Cardyi Olney. Annual, erect, the stem (0.6-1.6 m. high) and pedun- 

 cles glandular-bristly; leaves narrowly lanceolate, attenuate to both ends, 

 roughish ; sheaths ciliate or sometimes margined ; spikes slender, loose and nod- 

 ding ; flowers purplish ; stamens mostly 5. Swamps and recent clearings, Me. 

 to N. J., Ont., and Mich. 



19. P. Hydr6piper L. (COMMON SMARTWEED or WATER PEPPER.) Annual, 

 3-6 dm. high, smooth ; leaves narrowly lanceolate, very acrid and peppery; 

 spikes nodding, usually short or interrupted ; flowers mostly greenish ; stamens 

 6; style 2-3-parted ; achene dull, minutely striate. Moist or wet grounds; 

 apparently introduced southeastw., but indigenous northw. and westw. (Eu.) 



20. P. acre HBK. (WATER SMARTWEED.) Perennial, nearly smooth; 

 stems rooting at the decumbent base, 0.6-1.6 m. high ; leaves lanceolate, atten- 

 uate, 7-12 cm. long, taper-pointed ; spikes erect, rather dense, distinctly pedun- 

 cled; flowers white or flesh-color; stamens 8; style mostly ^-parted; achene 

 smooth and shining. (P. punctatum Ell., including var. robustius Small.) 

 Wet places; e. Mass., westw. and south w. (Trop. Am.) 



Var. leptostachyum Meisn. Annual, erect or slightly repent at the base, 

 3-6 dm. high ; leaves lanceolate, smaller, thinner, and lighter green than in the 

 type ; spikes elongated and very loosely flowered, not distinctly peduncled, the 

 widely scattered flowers commonly extending down to the upper leaf-axils. (P. 

 punctatum, var. Small.) Moist ground, common ; sometimes well marked, at 

 other times passing imperceptibly into the typical form. 



21. P. ORIENTALS L. (PRINCE'S FEATHER.) Tall branching annual, soft- 

 hairy; leaves ovate or oblong, pointed, distinctly petioled; sheaths ciliate or 

 often with an abrupt spreading border; flowers large, bright rose-color, in dense 

 cylindrical nodding spikes; stamens 7. Sparingly escaped from gardens into 

 waste grounds. (Introd. from India.) 



22. P. PERSICARIA L. (LADY'S THUMB.) Nearly smooth and glabrous (3-5 

 dm. high) ; sheaths more or less bristly-ciliate ; leaves lanceolate, pointed, 



