OCTANDRIA, TRIGYNIA. 189 
§ S. Spike paniculate, 
10. P. flowers octandrous, trigynous, spikes pani-articuiatum, 
culate, filiforoi^ flowers solitary, pedunculate ; 
bractes iinbricate-truncate ; leaves linear, och- 
rese sheathing-truncate, stem herb aceous.-?Fi7M. 
Jointed-leaved Knot-weed. 
A handsome species, about a foot high. Flowers rose-co- 
ioured mixed with white. In sandy fields of Jersey, within 
ten miles of Philadelphia; Mr. Collins. I have not found it; 
my specimens were brought me by Mr. Theophilus Beesley 
of Salem, from that neighbourhood. Annual. July, August. 
§ 4. Leaves incised) or cordate at the base. 
11. P. flowers in heads, octandrous, with the style saggittatum. 
3 -cleft ; stem retrorsely aculeate j leaves sag- 
gittsite.—Mich. 
Icon. Pluk. Mant. t. 389. f. 5. 
Jlrrow -leaved Tear-thumb. 
A weak, decumbent plant, with angular stems, prickly back- 
ward. Flowers white, or very pale rose-colour. In all swamps 
and bogs, and on the margins of meadow-drains, very com- 
mon. Annual. June to August. 
12. P. flowers distinct, hexandrous, with the style arifoiium. 
£-cleft; spikes few flowered; stem retrorsely 
aculeate ; leaves hastate. — Mich. 
Icon. Pluk. amalth. t. 398. f. 3. (Pursh.) 
Halbert-leaved Tear-thumb. 
A larger and rougher plant than No. 11. Easily known by 
its triangular -hastate leaves. Stems red, rigidly prickly back- 
ward, and tear the hands of those who meddle with the plant. 
Grows in similar places with No. 11. Annual. July, August. 
13. P. flowers octandrous, with the styles 3-cleft; convoiv«i«s,- 
leaves oblong-cordate; stem angled, roughen- 
ed ; calix of the mature fruit without wings.— 
Mich. 
Icon. FI. Dan. T44. 
