35 FLORA. 



of the calyx yellowish green, straight, enlarged around the ovary, the lobes appen- 

 daged; anthers equidistant. Near Ithaca and Flushing, N. Y., and E. Penn. Es- 

 caped from cultivation. Native of southern Europe. Summer. 



4. Aristolochia macroph^lla Lam. DUTCHMAN'S PIPE. (I. F. f. 1283.) A 

 twining vine, the stem sometimes 2.5 cm. in diameter and 10 m. long; leaves thin, 

 broadly reniform or suborbicular, densely pubescent beneath when young, glabrous 

 or nearly so, and 1.5-3.6 dm. broad when mature; petioles 2. 5-10 cm. long; pedun- 

 cles solitary or 2 or 3 together, about as long as the petioles, each with a suborbic- 

 ular clasping bract at about the middle 12-25 mm - * n diameter; calyx-tube strongly 

 curved, 2.5 cm. long or more, contracted at the throat, yellowish green, veiny, the 

 limb flat, spreading, purple-brown, somewhat 3-lobed; anthers contiguous in pairs 

 under the 3 lobes of the stigma; capsule oblong -cylindric, 5-7.5 cm. long. In rich 

 woods, S. Penn. to Minn., Ga., Tenn. and Kans. May-June. Fruit ripe Sept. 



5. Aristolochia tomentosa Sims. WOOLLY PIPE-VINE. (I. F. f. 1284.) 

 Similar to the preceding, but the twigs, petioles, leaves and peduncles persistently 

 tomentose. Leaves suborbicular or broadly ovate, 0.7-1.5 dm. broad when mature; 

 petioles rather stout; peduncles mostly solitary, bractless; calyx-tube sharply 

 curved, yellowish green, about 3 cm. long, its throat nearly closed, the limb dark 

 purple, 3-lobed; capsule oblong-cylindric. In woods, Mo., Kans., and S. 111. to 

 N. Car., Ala. and Fla. May-June. 



Order 13. POLYGONALES. 



Characters of the only family, Polygonaceae, as given below. 



Family i. POLYGONACEAE Lindl.* 

 Buckwheat Family. 



Herbs, twining vines, shrubs or trees, with alternate, or sometimes 

 opposite or whorled, simple mostly entire leaves, jointed stems, and 

 usually sheathing united stipules (ocreae). Flowers small, regular, per- 

 fect, dioecious, monoecious or polygamous. Petals none. Calyx inferior, 

 2-6-cleft or 2-6-parted, the segments or sepals more or less imbricated, 

 sometimes petaloid, sometimes developing wings in fruit. Stamens 2-9, 

 inserted near the base of the calyx ; filaments filiform or subulate, often 

 dilated at the base, distinct or united into a ring ; anthers 2-celled, the 

 sacs longitudinally dehiscent. Ovary superior, i-celled ; ovule solitary, 

 orthotropous, erect or pendulous; style 2-3-cleft or 2-3-parted, some- 

 times very short ; stigmas capitate or tufted, rarely 2-cleft ; fruit a lentic- 

 ular 3-angled or rarely 4-angled achene, usually invested by the persistent 

 calyx ; endosperm mealy ; cotyledons accumbent or incumbent ; embryo 

 straight or nearly so. About 30 genera and 800 species, of wide geo- 

 graphic distribution. 



Flowers subtended by involucres. 



Ocreae present ; calyx 2-4-parted ; stamens 3 or fewer. i. Macounastrum. 



Ocreae none; calyx 6-cleft or 6 parted ; stamens 9. 2. Eriogonum. 



Flowers not involucrate ; stamens 4-8. 

 Ocreae present ; stigmas tufted. 



Calyx 6-parted ; style 3-parted ; achene 3-angled. 3. Kumex. 



Calyx 4-parted ; style 2-parted ; achene lenticular. 4. Oxyria. 



Ocreae present ; stigmas capitate. 



Pedicels mostly several together; achene much surpassing the calyx. 



5. Pagopyrum. 

 Pedicels usually fascicled ; achene mostly enclosed by the enlarged calyx. 



6. Polygonttm, 

 Pedicels solitary ; leaves jointed at the base. 7. Potygonella. 



Ocreae obscure or wanting ; stigmas 2-cleft. 8. Brunnichia. 



* Contributed by Dr. JOHN K. SMALL. 



