A NEW POLYGONUM FROM BOLIVIA POLYGONUM FALLAX.
Annual or perennial by a long somewhat spiral root, low, dull green. Stem more or less densely and caespitosely branched near the top of the root, the branches spreading or prostrate and as cending, 2-12 cm. long, very leafy except at the base ; leaves varying from ovate-oblong to obovate-oblong, 3-5 mm. long, ob tuse, somewhat revolute and crisped, narrowed at the base, wrinkled above, slightly nerved beneath, the mid-nerve keeled beneath, es pecially near the base, obliquely articulated at the base of the ocreae ; ocreae funnelform, 4 mm. long, imbricated, especially to ward the ends of the branches, at length lacerate to a little below the middle ; flowers numerous and often crowded ; calyx 2.5 mm. long, 5-parted, 4 segments green, with whitish margins, i wholly included and hyaline, all rounded at the apex, stamens usually 5 or 6; filaments dilated their whole length into a broadly ovate hyaline petal-like organ ; style two-parted, .4 mm. long ; achene lenticular, ovoid, 2.5 mm. long, reddish, nearly smooth, shining, its faces convex, its angles rounded, sometimes faintly margined.
A species of especial interest collected in Bolivia by Mr. Bang and communicated to me by Dr. Rusby. Although it belongs to
the subgenus AVIC1Ilaria, its fruit possesses characters heretofore unknown in that subgenus. The several natural groups of Polu onum bear two kinds of achenes, some lenticular, others trique trous, while in a few cases both forms appear. Avicularia has been known to produce only the triquetrous achenes developed from a three-angled ovary with a more or less three-branched style, but in Polygonum fallax we are confronted with a species of subgenus Amcularia bearing only lenticular achenes developed from lenticular ovaries with two-branched styles.
A second peculiarity is exhibited in the pericarp which most closely resembles that of the different members of the subgenus Thiravuz, both in texture and color, but the styles are not those of that group. Another interesting point is found in the androecium ; the filaments are dilated into broad petal-like organs, which form a cup around the ovary. I know no other case like this in the genus. Notwithstanding these exceptions, the species for the present must be referred to Ay/or/aria and forms the first excep tion to its normal morphology as far as I have observed, and an interesting one.