479 
southeastern Missouri, growing in the swamps of that region. 
This, like the preceding, follows the Mississippi River northward, 
and also shows the same variation in the amount and strength of 
the Strigose pubescence as do the Southern individuals of this 
species. 
Potyconum persicarioipes H.B.K. Nov. Gen. 2: 179 (1817). 
This species has been found within the limit of the Northern 
Flora by Mr. H. J. Webber on the Dismal River, Nebraska. The 
Specimens of the collection are not numbered, but are dated July 
14, 1889. 
Potyconum Carey! Olney, Proc. Prov. Franklin Soc. 1: 29 (1847). 
There is an unnamed specimen of the above, lying in the Her- 
barium of the Academy of Natural Science at Philadelphia, col- 
lected by Dr. Pitcher at Fort Gratiot, Michigan. No date is 
iven, but the specimen was evidently found a number of years 
before the originals of Olney were collected. 
‘ PotyGonum BOREALE (Lange). 
Polygonum aviculare L. var. boreale Lange, Consp. Fl. Greenl. 
105 (1880), ; : 
Annual, glabrous, herbaceous and somewhat fleshy. Stem 
ascending 1-2 dm. long, simple or sparingly branched; leaves 
obovate, oblong or elliptic-obovate, 1-3 cm. long, .5—1 cm. broad, 
obtuse, slightly papillose, somewhat acuminate at the base, short- 
Petioled, mid-rib alone prominent; ocrez oblique 5—7 mm. long, 
silvery or brownish, only slightly lacerate; axillary clusters 2-5 
flowered ; pedicels slender; 3-4 mm. long, 5-parted to below the 
middle, calyx 4 mm. long, segments obtuse, light green, with — 
white or cream-colored borders inclined to be open; stamens 6, 
Included ; filaments short and stout; style 1 mm. long, 3-parted — 
to the base; achene ovoid, 3.5 mm. long, triquetrous, somewhat 
Pointed, dull and striate-reticulated. (Plate 224.) : ; 
I have now seen this form from two Greenland collections and 
can not find any characters that warrant its disposal as a variety 
of P. aviculare. . g 2 
The general character of the plant is different from that species, _ y 
and the diagnosis as given above will serve to separate it, One eos 
of the best distinctions is in the fruit. P. aviculare has a pyra-— 
_ Midal-ovoid achene, whereas that of P. doreale is simply ovoid and - 
