190 COMMON CANADIAN WILD PLANTS. 



Var. inearna'tum, Watson, has the spikes more slender 

 and elongated, nodding. 



Var. inea'num, Kooh, is 6-12 inches high, with small 

 leaves more or loss flocculent-lioary underneath, and short 

 spikes. Chiefly eastward and N. W. 



6. P. Pennsylvan'ieum, L. Sheaths not fringed, stem 

 1-3 feet high, the upper branches and the 2Jedundes bristly 

 joith stalked glands. Spikes thick, erect. Stamens 8. Achene 

 flat. — Low open grounds. 



7. P. Persiea'ria, L. (Lady's Thumb.) Sheaths with a, 

 somewhat oiliate border. Stem nearly smooth, a foot or more 

 in height. Leaves with a dark blotch on the m.iddle of the 

 upper surface. Spikes dense, erect, on naked peduncles. 

 Stamens 6. Aciene flat or 3-angled, according- as the stig- 

 mas are 2 or 3. — Very common near dwellings in moist 

 ground. 



8. P. amphib'ium, L. (Water Peesicaria.) Spike of 

 flowers dense, oblong, showy, rose-red. Stem floating in 

 shallow water or .rooting in soft mud, nearly glabrous. 

 Leaves long-petioled, often floating. Sheaths not bristly- 

 fringed. Stamens 3, Stigmas 2.^-In shallow water, mostly 

 northward . 



9. P. Muhlenberg'li, Watson, differs from the last in 

 being rough with appressed hairs all over. — Ditches. 



10. P. Hartwrighfii, Gray, is distinguished from P. 

 amphimum^by its foliaceous and ciliate sheaths. — Muddy 

 margins of ponds and lakes. 



11. P.hydFOpipePOi'des, Miohx. (Mild Water-Pepper.) 

 Stem slender, 1-3 feet high, in shallow water. Leaves narrow, 

 roughish. Sheaths hairy and fringed with long bristles. 

 Spikes slender, erect, pale rose-coloured or whitish. Stamens 

 S. Stigmas 3. Achene 3-angled.— In shallow water. 



12. P. acre, H. B. K. (Water Smartweed.) Sheaths 

 fringed with bristles. Leaves transparent-dotted. Stem root- 

 i,-.g at the decumbent base, 2-4 feet high, in shallow water 

 or muddy soil. Leaves narrow, taper-pointed. Spikes 



