Amaranthaceae
Including Chenopodiaceae of Michigan Flora.
An important character is often whether the fruit is vertical (its longer axis being the axis of the flower) or horizontal (its longer axis at right angles to the axis of the flower). A number of species become a rich red-purple in the fall. Many species are annual weeds of dry or even saline sites.
1. Leaves opposite; either much reduced and scale like or with white silky-woolly hairs on both surfaces.
2. Leaves linear-lanceolate; stem and leaves (both surfaces) with white silky-woolly hairs.
2. Leaves much reduced and scale-like, scarious, glabrous, connate; stem branches succulent, glabrous, appearing jointed, the flowers entirely sunk in the fleshy internodes.
1. Leaves alternate (or the lower sometimes opposite), well developed but without white silky-woolly pubescence.
3. Leaf tips with a sharp spine over 0.5 mm (usually ca. 1 mm, even longer on bracts subtending flowers); leaves filiform, ± terete; fruit horizontal, ca. 1-1.3 mm long, slightly broader, covered by the perianth; tepals with transverse keel or wing sometimes longer than body of tepal.
3. Leaf tips at most with mucro less than 0.5 mm long; leaves various in width, flat; fruit and perianth various.
4. Flowers unisexual (plants monoecious or dioecious); tepals and bracts acute, scarious or fruit in most if not all flowers enveloped by a pair of bracteoles (perianth absent).
5. Bracts and tepals all acute, scarious.
5. Bracts beneath pistillate flowers broad and usually tuberculate and toothed with margins partly fused, obtuse to acute but herbaceous in texture (or even hardened in one species), tepals herbaceous.
4. Flowers mostly bisexual; fruit not enveloped by bracts but perianth may cover it; bracts herbaceous or firm and hardened, not scarious.
6. Leaves linear to narrowly lanceolate, less than 4 (-6) mm broad, entire, 1 (-3)-nerved.
7. Plant with numerous delicate spines ca. 1-3 mm long in inflorescence (sterile pedicels and branch-tips); leaves without spines; fruit all horizontal.
7. Plant without spines in inflorescence (or these less than 0.5 mm long and also on leaves); leaves and fruit various.
8. Inflorescence and leaves beneath farinose; flowers crowded on short branches that exceed their subtending bracts.
8. Inflorescence and leaves not farinose; flowers 1-3 in the axils of longer bracts.
9. Leaves and bracts green to the tips, not mucronate; bracts long-ciliate, especially basally; fruit horizontal, round, less than 1 mm long, enclosed by the perianth (each tepal with a transverse wing).
Bassia (in part)
9. Leaves when intact tipped with a non-green sharp mucro less than 0.5 mm long (no longer, or even absent, on bracts subtending flowers); bracts glabrous to pubescent but not long-ciliate; fruit various.
10. Fruit vertical, flattened, usually narrowly wing-margined, ca. (2-) 3-4.5 mm long, greatly exceeding the tiny scarious perianth; sandy (not saline) habitats.
10. Fruit horizontal (or mostly so), less than 1 mm long and 1.5 mm broad, enclosed by the perianth; saline habitats.
6. Leaves usually at least 4 mm broad, toothed to sinuate or crenulate on the margin (if entire, then pinnate- or triple-nerved and not linear).
11. Plant from a stout swollen tap root, rarely persisting from cultivation or in disturbed ground; principal leaves at least 3 cm broad, the margins crenulate and ± undulate.
11. Plant with tap root, if present, no thicker than stem, not cultivated (though some species weedy); principal leaves narrower and/or prominently dentate with coarse teeth (or hastate).
12. Fruit horizontal, completely encircled by the connate wing of the perianth; styles 3.
12. Fruit horizontal or vertical, but the perianth without connate wing; styles usually 2.
13. Tepals with transverse (but separate) wings; leaves entire, not over 5 mm wide; fruit horizontal; bracts long-ciliate, especially basally.
Bassia (in part)
13. Tepals not transversely winged (may be keeled); leaves and fruit various; bracts not ciliate.
14. Leaves (and rest of plant) neither glandular nor pubescent, but farinose in some species.
Chenopodium (in part)
14. Leaves with yellow to orange resinous glands or gland-tipped hairs at least beneath, not farinose; bruised plant strongly aromatic.
Dysphania (in part)
Citation:
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. March 31, 2025
https://mifloradev.lsa.umich.edu/flora-demo/#/family/Amaranthaceae