120 COMMON CANADIAN WILD PLANTS. 



4. P Peimsylva'nicum, L. -Sheaths not fringed. Stem 1-3 

 feet high, the upper hr<tm-h<>x <tn<l, ttir polunchx .V/V/// irith 

 glands. Spikes thick, erect. Stamens 8. Achene fla. Low open 

 grounds. * 



5. P. Persica'ria, L. (LADY'S THUMB.) Sheaths with a some- 

 what ciliate border. Stem nearly smooth, a foot or more in height. 

 Leaves with a dark blotch on the middle of the upper surface. Spikes 

 dense, erect, on naked peduncles. Stamens G. Achene flat or 

 3-angled, according as the stigmas are 2 or 3. Very common 

 near dwellings in moist ground. 



6. P. amphib'ium, L. (WATER PERSICARIA.) Spike of 

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

 water or rooting in soft mud, nearly glabrous. Leaves long- 

 petioled, of ten floating. Sheaths not bristly- fringed. Star 

 Stigmas 2. In shallow water, mostly northward. 



7. P. Muhlenberg'ii, Watson, differs from the last in being 

 rough with appressed hairs all over. Ditches. 



8. P. Hartwright'ii, Gray, is distinguished from P. am- 

 phibium by its foliaceous and ciliate sheaths. Muddy margins of 

 ponds and lakes. 



9. P hydropiperoi'des, Michx. (MiLD WATER- PEPPER.) 

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

 roughish. Sheaths hairy and fringed with long bristles. Spikes 

 slender, erect, pale rose-coloured or whitish. Stamens 8. Stig- 

 mas 3. Achene 3-angled. In shallow water. 



10. P. acre, H.B K (WATER SMARTWEED.) Sheaths fringed 

 with bristles. Leaves transparent-dotted. Stem rooting at tne 

 decumbent base, 2-4 feet high, in shallow water or mini 

 Leaves narrow, taper-pointed. Spikes slender, erect, pale rose- 

 coloured. Sepals g/andtdar-dotted. Stamens 8. Achene 3-angled, 

 shining. Muddy soil or shallow water. 



11. P. Hydrop'iper, L. (COMMON SMARTWEED or WAT F.I i- 

 ri-:i'iM-:u.) Sheaths and leaves as in the last, the leaves, ho. 

 larger. Spikes s-ender, nodding, greenish. Sepals gland afar- 

 dotted. Stamens 6. Achene dull. Wet places. 



12. P. Virginia'num, L. Calyx greenish, uneqiMlly4-i 

 Stamens 5. Styles 2, persistent on the flat acheno. Flo 1 /. 



