abronia POLYGONACE.E 567 



and fleshy, prostrate very viscid-pubescent 1-3 feet long, from a long fleshy 

 perennial root: leaves chick, broadly ovate to reniform 6-18 lines long, obtuse, 

 on short thick petioles: peduncles usually exceeding the leaves: bracts of 

 the involucre 5, rounded to ovate or oblong 2-4 inches long: flowers numer- 

 ous 5-6 lines long bright yellow, very fragrant, the lobes emarginate: fruit 

 4-6 lines long, coriaceous, acute at each end, the wings more or less unequally 

 developed, usually narrow. On sand- banks along the coast, Vancouver Island 

 to California, 



A. fragraiis Nutt. Hook. Kew Jouru. Bot. v, 261. More or less vis- 

 cid-puberulent: stems several, from a perennial root, herbaceous, 6-20 inches 

 high, erect or ascending, usually much branched: leaves oblong or ovate, 1-3 

 inches long, truncate, more or less cuneate at base, obtuse to acute: peduncles 

 mostly solitary: bracts of the involucre large, broadly ovate, white and scari- 

 ous 4-9 lines long: flowers white, very numerous in the involucres, 5-10 lines 

 long, opening at night: fruit 3-6 lines long, coriaceous, with narrow undulate 

 wings which do not close over the ovary; In dry soil eastern Washington 

 to Iowa. 



Order LXXV POLYGOXACE^ Lindl, Nat. Syst. 211. 



Herbs shrubs or trees with jointed stems, watery, often acid 

 or acrid, juice, alternate, opposite or whorl ed simple mostly en- 

 tire leaves with sheathing united stipules and regular perfect, 

 dioecious, monoecious or polygamous flowers. Calyx free from 

 the ovary, 2-6-cleft or 2-6-parted, the segments or sepals more 

 or less imbricated, often petal-like stamens 2-9, inserted near 

 the base of the calyx, or in staminate flowers crowded toward 

 the center. Ovary superior, 1-celled, with a solitary erect or 

 pendulous orthotropous ovule. Style 2-3-cleft or 2-4-parted, 

 sometimes very short stigma, capitate or tufted, rarely 2 -cleft. 

 Fruit a lenticular 3-angled or rarely 4-angled achene, usually 

 invested by the persistent calyx. Embryo straight or curved 

 in mealy albumen. 



Tribe i Herbs or somewhat shrubby plants. Flowers 

 involucrate. 



1 Eriogonum Involucre several-flowered with 4-8, pointless teeth : flow- 



ers exserted: stamens 9: achenes mostly 3-angled. 



2 Oxytheca Involucre few-flowered, herbaceous, with 3-5 straight acute 



or awned lobes : flowers on exserted pedicels, pubescent : stamens 9 : 

 achenes lenticular. 



3 Chorizantlie Involucre 1-3-flowered, coriaceous or chartaceous, 3-6 



angled, with 3-6 cuspidate often hooked teeth and sometimes as many 

 cuspidate divaricate spurs at base : flowers usually included : stamens 

 3, 6 or 9 : achenes 3-angled. 



4 Pterostegia Slender annuals with opposite toothed or lobed leaves : 



involucre bract-like, with a solitary included flower. 



Tribe ii Herbs with alternate leaves and scarious sheathing 

 stipules. Flowers not involucrate. 



5 Polygonum Sepals 4-6, equal, appressed to the triangular or lenticu- 



lar achene : styles 2 or 3 : stigmas capitate. 



