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Published In: Proceedings of the American Academy of Arts and Sciences 12: 273–274. 1877. (Proc. Amer. Acad. Arts) Name publication detailView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 8/4/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native

 

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3. Amaranthus blitoides S. Watson (tumbleweed, prostrate amaranth, spreading pigweed)

Pl. 198 f; Map 812

Plants monoecious. Stems 10–70 cm long, spreading to less commonly loosely ascending, often forming dense mats, glabrous or sparsely pubescent with inconspicuous, mostly multicellular hairs, unarmed. Leaves short- to long-petiolate. Leaf blades 0.5–2.0(4.0) cm long, oblong-elliptic to obovate, rounded or shallowly notched at the tip (the midvein sometimes extending as a minute, sharp point), tapered at the base, glabrous. Inflorescences grayish green to green, all or nearly all axillary; mostly dense, small, globose clusters, with a short, terminal spike rarely also present. Bracts 1.0–2.5 mm long, those of the pistillate flowers about as long as the sepals, lanceolate to oblong-lanceolate, narrowed or tapered to a sharply pointed tip, with a somewhat thickened midrib, green or sometimes with narrow, thin, papery margins, the midrib sometimes extending beyond the main body as a minute awn, somewhat spinelike at maturity. Staminate flowers with 4 or 5 more or less similar sepals, these 1.3–2.0 mm long, erect or very slightly outward-curved, lanceolate to narrowly oblong-elliptic, narrowed or tapered to a minute, awnlike extension of the midrib at the tip. Stamens 3. Pistillate flowers with 4 or 5 sepals (the inner sepals somewhat shorter and narrower than the outer ones), these 1.2–2.7 mm long, erect or somewhat outward-curved, lanceolate to ovate or narrowly oblong-elliptic, narrowed or tapered to a blunt or sharp point. Stigmas 3, spreading. Fruits 1.5–2.1 mm long, with circumscissile dehiscence, the surface smooth or nearly so when dry. Seeds 1.3–1.7 mm in diameter, rounded along the rim, the surface black. 2n=32. July–October.

Scattered nearly throughout Missouri, but uncommon to absent in the southeastern quarter of the state (western U.S. [including Alaska] east to North Dakota and Texas; Canada; introduced eastward to Maine and Florida, as well as to Mexico, Caribbean Islands, Europe, and Asia). Banks of streams and rivers, bases of bluffs, and talus slopes; also roadsides, railroads, pastures, and open, disturbed areas.

Steyermark (1963) and many earlier authors called this species A. graecizans L., but that name has been shown to apply to a species native to the Mediterranean region with only two North American records (from New Jersey), apparently from plants introduced in ship’s ballast during the nineteenth century (Sauer and Davidson, 1961; Costea et al., 2001b).

 
 


 

 
 
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