160 CHENOPODIACEAE (GOOSEFOOT FAMILY) 



margins: stamens 3-5: achene triangular, narrowly ovoid, prominently granu- 

 lar in ridges. P. imbricatum. (P. unifolium Small, Mem. N. Y. Bot. Gard. 

 1: 129. 1900.) Alpine and subalpine; Colorado and Wyoming west to the 

 Pacific States. 



26. Polygonum Kelloggii Greene, Fl. Francis. 134. 1891. Low slender 

 glabrous annual, divergently branched from the base; the branches 2-5 cm. 

 long: leaves linear or nearly so, crowded but spreading rather than imbricated; 

 sheaths lacerate : flowers axillary (because of the short internodes the inflores- 

 cence appears like a leafy raceme) : calyx green, its obtuse segments whitish 

 or cream-color: stamens about 5, included: stigmas sessile or nearly so; achene 

 triangular, rhombic-ovoid, light brown, granular, and somewhat striate. 

 Colorado and Wyoming and west to the coast States. 



27. Polygonum Convolvulus L. Sp. PI. 364. 1753. Annual, twining or 

 procumbent, low, roughish, the joints naked: leaves halberd-heart-shaped, 

 pointed: flowers in small interrupted corymbose racemes: outer calyx-lobes 

 keeled : achenes smoothish. BLACK BINDWEED. Cultivated and waste grounds 

 throughout the United States. 



28. Polygonum scandens L. 1. c. Perennial, smooth: sheaths naked: leaves 

 cordate or slightly halberd-shaped, pointed: racemes interrupted, leafy: the 

 outer calyx-lobes strongly keeled and winged in fruit, the wings somewhat 

 crenate, but often one or all three wanting: achene over 3 mm. long, smooth 

 and shining. P. dumetorum scandens. CLIMBING FALSE BUCKWHEAT. Moist 

 thickets; from our range to the Atlantic States. 



37. CHENOPODIACEAE. GOOSEFOOT FAMILY 



Annual or perennial, herbaceous or shrubby, usually with simple alternate 

 exstipulate leaves. Flowers perfect or unisexual, small, green or greenish, 

 regular or nearly so, variously clustered or more rarely solitary in the axils, 

 ebracteate or with herbaceous bracts, which may become either a thin or 

 coriaceous pericarp inclosing the fruit. Perianth of 5 or fewer usually her- 

 baceous and persistent sepals. Stamens as many as the sepals and opposite, 

 distinct, with 2-celled anthers. Ovary 1-celled, with a solitary ovule, becom- 

 ing an achene or utricle. Mostly plants of saline soils. 



Embryo annular or folded on itself. 

 Flowers perfect, bractless. 

 Perianth wingless, persistent. 

 Two-five parted or divided. 



Lobes herbaceous, keeled 1. Chenopodium. 



Lobes becoming fleshy and red 2. Blitum. 



One sepal only. 



Herbaceous and bract-like 3. Monolepis. 



Hyaline and scale-like 4. Corispermum 



Perianth horizontally winged. 



Plant annual 5. Cycloloma. 



Plant perennial G. Kochia. 



Perianth saccate, fleshy; stems fleshy, leafless . . . . 7. Salicornia. 



Flowers monoecious or dioecious; perianth in fertile flowers wanting. 



Fruiting bracts compressed ....... 8. Atriplex. 



Fruiting bracts obcompressed. 

 Pericarp naked. 



Orbicular, wing-margined ....... 9. Grayia. 



Subhastate, 2-toothed at apex . . . . . .10. Suckleya. 



Pericarp silky-pubescent 11. Eurotia. 



Embryo spirally coiled. 



Flowers monoecious; plant shrubby; fruit winged . . . .12. Sarcobatus. 

 Flowers perfect; plants herbaceous. 



Leaves spiny at maturity; fruit winged 13. Salsola. 



Leaves not spiny; fruit not winged ...... 14. Sueda. 



1. CHENOPODIUM L. GOOSEFOOT. PIGWEED 



Annual herbs with alternate petioled leaves. Flowers small, green, sessile, 

 in axillary terminal or panicled spikes; lobes of the perianth usually somewhat 



