570 



CHEXOPODIACEAE. 



i. CHENOPODIUM L. Sp. PI. 218. 1753. 



Annual or perennial, green and glabrous, white-mealy or glandular-pubescent herbs, with 

 alternate petioled entire sinuate-dentate or pinnately lobed leaves. Flowers very small, 

 green, perfect, sessile, bractless, clustered in axillary or terminal, often panicled or 

 compound spikes. Calyx 2-5-parted or 2-5-lobed, embracing or enclosing the utricle, its 

 segments or lobes herbaceous or slightly fleshy, often keeled or ridged. Stamens 1-5; fila- 

 ments filiform or slender. Styles 2 or 3; seed horizontal or vertical, sometimes in both posi- 

 tions in different flowers of the same species, firmly attached to or readily separable from the 

 pericarp; endosperm mealy, farinaceous; embryo completely or incompletely annular. 

 [Greek, goose-foot, from the shape of the leaves.] 



About 60 species, mostly weeds, of wide geographic distribution. Besides the following, some 

 5 others occur in the western parts of North America. 



K- Embryo a complete ring. 

 Leaves white -mealy on the lower surface. 



leaves or some of them sinuate-toothed or lobed. 

 Sepals strongly keeled in fruit. 



Pericarp firmly attached to the seed; stem erect, tall. 

 Pericarp readily detached from the seed; stem low. 

 Sepals not keeled in fruit; stem decumbent. 

 Leaves mostly entire, narrowly linear or oblong. 



Leaves green and glabrous or nearly so on both surfaces when mature. 

 Leaves oblong or ovate-oblong, entire. 

 Leaves, at least the lower, sinuate, toothed or incised. 

 Stamens 5; calyx not fleshy. 



Pericarp readily separable from the seed. 



Leaves oblong or lanceolate ; calyx-lobes scarcely keeled. 

 Leaves triangular-hastate; calyx-lobes keeled. 

 Pericarp firmly attached to the seed. 



Flower-clusters, at least the upper, longer than the leaves. 



Leaves oblong, rhombic-ovate or lanceolate, narrowed at the base. 



Leaves obtuse or merely acute. i. C. album -stride. 



Leaves or some of them cuspidate or bristle-tipped. 7. C. Berlandieri. 

 Leaves triangular-ovate, truncate or subcordate at base. 8. C. urbicum. 

 Spikes loosely panicled in the axils, the panicles shorter than the leaves. 



9. C. murale. 



Stamens only i or 2: calyx slightly fleshy, red. 

 Leaves very coarsely 2-6-toothed. 



Leaves broadly triangular-hastate, entire or merely undulate. 

 X- -X- Embryo an incomplete ring. 



Leaves ovate or oblong, pinnately lobed; flowers in long loose panicles. 

 Leaves lanceolate ; flowers in continuous or interrupted spikes. 

 Spikes borne in the axils of the numerous small upper leaves. 

 Spikes in large commonly leafless terminal panicles. 



i. C. album. 



6. C. Fremontii incamtm. 



2. C. glaucum. 



3. C. leptophyllum. 



4. C. polyspermum. 



5. C. Boscianuni. 



6. C. Fremontii. 



i. Chenopodium album 



11. C. rnbrnm. 

 10. C. hybridum. 



12. C. Bonus-Henricns. 



13. C. Bottys. 



14. C. ambrosioides. 



15. C. anthelminticnm. 



Lamb's Quarters. White Goosefoot. Pigweed. 

 (Fig. 1359.) 



Chenopodium album L. Sp. PI. 219. 1753. 



Annual, pale green, stem usually slender, stri- 

 ate and grooved at least when dry, erect, com- 

 monly much branched, i-io tall, the branches 

 ascending. Leaves rhombic-ovate or the upper 

 lanceolate or linear-lanceolate, narrowed at the 

 base, acute or sometimes obtuse at the apex, 3- 

 nerved, white-mealy beneath, dentate, sinuate or 

 lobed, or the upper entire, i'-4' long; petiole 

 often as long as the blade; spikes terminal and 

 axillary, simple or compound, often panicled; 

 calyx about }/z" broad in fruit, its segments 

 strongly keeled, usually completely enclosing 

 the utricle; seed horizontal, black, shining, 

 firmly attached to the pericarp; embryo a 

 complete ring. 



In waste places. A common weed throughout 

 North Amenca except the extreme north. Natur- 

 alized from Europe. Native also of Asia. Widely 

 distributed as a weed in all cultivated regions. 

 Stem often purple-streaked. June-Sept. 

 Chenopodium album viride (L.) Moq. in DC. Prodr. 13: Part 2, 71. 1849. 

 Chenopodium :;';-/</< L. Sp. PI. 219. 1753. 



Plant brighter green; leaves green orTboth sides or but slightly mealy beneath. Range of the 

 type. Perhaps a distinct species. 



