POLYGON ACfi^. 189 



1. ERIOG'ONUM, Klchz. 



1. E. fla'vum, Nutt. Woolly throughout, a few inches 

 high. Leaves oblanoeolate. Umbel of 3-9 rays, on a naked 

 peduncle. Flowers yellow, silky. — N.W. 



a. POtYft'OSUM, L. Knotweed. 



* Flowers along tlie stem^ inconspicuous, greenish-white, nearly sessile 

 in the axils of the small leaves. Slieatks cut-fringed or torn. 



1. P. marit'imum. L. (Coast Knotgrass.) Prostrate 

 with stout stems, glaucous. Leaves thick, oval to narrowly 

 oblong. Flowers in the axils of leaves, clustered. Stipules 

 very conspicuous. Stamens 8. Achenes smooth and shin- 

 ing, projecting above the calyx. — Sea-coast. 



2. P. avieula're, L. (Knotgeass. Goosegeass.) A weed 

 everywhere in yards and waste places. Stem prostrate and 

 spreading. Stamens chiefly 5, Achene 3-sided, duU. 

 Stigmas 3. Leaves sessile, lanceolate or oblong. Var. 

 ereetum. Both. (P. erectum, L.) is upright and larger, with 

 broader leaves. 



3. P. ramosis'simum, Michx. Erect or ascending, yel- 

 lowish-green. Leaves lanceolate to linear, acute, very small 

 above. Sepals mostly 6 ; stamens 3-€. Achene smooth and 

 shining. — Chiefly westward ; sandy places. 



4. P. ten'ue, Michx. Stem slender, upright, sparingly 

 branched, angled. Leaves sessile, narrowly linear, verj 

 acute, 3-nerved. Stamens 8. Achene dull black. — Dry soil 

 and rocky places. 



* * Flowers in terminal spikes or racemes, mostly rose-coloured or 

 pinkish, occasionally greenish. 



-*- Leaves not heart-shaped or arrow-shaped. 



5. P. lapathlfo'lium, L. Sheaths not fringed, stem 

 nearly smooth, 8-6 feet high. Leaves long, tapering from 

 aear the base to a narrow point, rough on the midrib and 

 margins. Spikes oblong to linear and erect or nearly so. 

 Stamens 6. Styles 2. Achene flat or hollow-sided. — In muddy 

 places along streams and ponds. 



