8. Amaranthus hypochondriacus L. (Prince’s feather)

A. hybridus L. var. hypochondriacus (L.) B.L. Rob.

Map 817

Plants monoecious. Stems 30–250 cm long, erect or ascending, glabrous or sparsely to moderately pubescent toward the tip with inconspicuous, mostly crinkled, multicellular hairs, unarmed. Leaves long-petiolate. Leaf blades 2–15 cm long, lanceolate to ovate or elliptic, narrowed or tapered to a sharply or rarely bluntly pointed tip, narrowed or tapered at the base, the surfaces glabrous or the undersurface sparsely pubescent mostly along the veins with inconspicuous, mostly crinkled, multicellular hairs. Inflorescences usually red or yellow, less commonly mostly bright green, axillary and terminal, the axillary inflorescences short to long spikes, the terminal inflorescence usually a panicle with few to many clusters of short to long, dense spikes (these branching along mostly the lower half of the panicle axis), the flowers mostly continuous along the spikes, the tip stiffly straight or nearly so, the main axis and branches moderately pubescent with mostly crinkled, multicellular hairs. Bracts 2.6–3.4 mm long, about as long as to slightly longer than the fruits, lanceolate to ovate, narrowed or tapered to a sharply pointed tip, with a moderately thickened green midrib and broad, thin, papery margins, the midrib extending beyond the main body as a short awn, often somewhat spinelike at maturity. Staminate flowers with (4)5 more or less similar sepals, these 3.0–3.3 mm long, straight, narrowly oblong to ovate, narrowed or tapered to a bluntly or more commonly sharply pointed tip, usually with a minute, awnlike extension of the midrib. Stamens 5. Pistillate flowers with (4)5 more or less similar sepals, these 1.7–2.3 mm long, slightly and inconspicuously overlapping, more or less straight at the tip, oblong-elliptic to ovate, bluntly to more commonly pointed, usually with a short, awnlike extension of the midrib. Stigmas 3, spreading from a thickened, erect base. Fruits 2.0–2.4 mm long, with circumscissile dehiscence, the surface smooth or finely wrinkled when dry. Seeds 1.0–1.3 mm in diameter, angled along the rim, the surface pale dark brown to black or less commonly whitish yellow. 2n=32. July–October.

Introduced, known thus far only from a single historical collection from Jackson County (originated in Latin America, widely cultivated in tropical and warm-temperate regions, escaping sporadically in the U.S.). Gardens and open, disturbed areas.

As noted in the treatment of A. cruentus, Steyermark’s (1963) original report of this taxon was based on two Boone County specimens that subsequently were redetermined as A. cruentus. However, Costea et al. (2001a) reported a new record from Jackson County, which Steyermark had misdetermined earlier as A. caudatus. Amaranthus hypochondriacus is a principal crop amaranth, one of the cultigens derived long ago in Latin America, probably from selected strains of A. powellii or, more likely, from hybrids between A. cruentus and A. powellii.