134 CHENOPODIACEAE. 



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sinuate-dentate or pinnately-lobed ; flowers very small, green, 

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

 panicled or compound spikes; calyx 2-5-parted or lobed; stamens 

 1-5; utricle embraced or enclosed by the calyx, the segments of 

 which are herbaceous or slightly fleshy in fruit; endosperm mealy. 



Calyx somewhat fleshy and often red in fruit; stamens 1 or 2. C. humile. 

 Calyx not fleshy nor red; stamens 5. 



Leaves mealy beneath. C. album. 



Leaves green and glabrous or very slightly mealy. 



Calyx-lobes keeled; teeth of the leaves few. C. hybridum. 



Calyx-lobes not keeled; teeth of the leaves numerous. 

 Seeds dull; axillary flower clusters shorter than the 



leaves. C. murale. 



Seeds shiny; axillary flower clusters mostly longer 



than the leaves. C. urbicum. 



Chenopodium humile Hook. Stems usually decumbent, much branched, 

 low; leaves ovate or lanceolate, often hastate, 2-5 cm. long, dentate or entire, 

 green; flower clusters in the axils of the upper leaves; seed small, 0.5 mm. broad. 



Along the seashore, not common. 



Chenopodium album L. Lamb's Quarters. Pigweed. Erect, stout, 50- 

 100 cm. tall, usually simple below the inflorescence, more or less white-mealy 

 throughout; leaves rhombic-ovate, sinuate or dentate, obtuse or acute, 2-4 

 cm. long, greener above; petioles slender, nearly equalling the blade; upper- 

 most leaves lanceolate and entire; panicle commonly 30 cm. long; spikes 

 axillary or terminal, rather dense; fruiting calyx 1 mm. broad, the sepals 

 keeled and arched over the lenticular fruit; seed black, minutely pitted. 



A common introduced weed. 



Chenopodium hybridum L. Green and glabrous throughout or the inflo- 

 rescence a little mealy, erect, 60-120 cm. high; leaves triangular-ovate, acu- 

 minate, somewhat cordate at base, thin and rather large, 520 cm. long, with 

 a few large teeth on each side; inflorescence a loose panicle; flowers in small 

 clusters in leafless racemes; calyx-lobes keeled, shorter than the fruit. 



In waste places, introduced from Europe. 



Chenopodium murale L. Annual, green, slightly or not at all mealy; 

 stems erect or nearly so, branched, 30-70 cm. high; leaves rhombic-ovate, 

 acute, truncate to cuneate at base, coarsely and unequally dentate, 510 cm. 

 long; axillary flower clusters diverging, shorter than the leaves; seeds dull, 

 sharp-edged. 



A weed from Europe, occasionally found in waste places. 



Chenopodium urbicum L. Annual, green and glabrous or slightly mealy; 

 stems erect, usually branched, 30-80 cm. tall; leaves triangular-ovate, acutish, 

 mostly truncate at base, coarsely dentate, the larger ones 8-12 cm. long; 

 axillary flower clusters narrow, erect, the upper ones longer than the leaves; 

 seeds shiny, rounded on the edge. 



Native of Europe, sparingly introduced as a weed in waste places. 



Family 35. AMARANTHACEAE. AMARANTH FAMILY. 



Weedy herbs; leaves thin, simple, mostly entire, alternate or 

 opposite; flowers small, green or white, perfect, monoecious, 

 polygamous or dioecious, bracteolate, usually in terminal spikes 



