Aeschynomene rudis Benth. (rough jointvetch)

Map 1707

Stems 1–2 m tall, erect, often expanded toward the base and pithy, the upper portion moderately pubescent with pustular-based spreading hairs to 2 mm long. Leaves with 40–50 leaflets, the petiole 10–12 mm long, the rachis 9–12 cm long, the petiole and rachis pubescent with pustular-based nonglandular, whitish hairs. Stipules 8–10 mm long, 4–5 mm wide. Leaflets 8–16 mm long, 2–3 mm wide. Inflorescences usually on reduced lateral branches with few to several reduced pinnately compound leaves, appearing as branched, lax, racemose clusters 3–5 cm long (rarely reduced to a solitary flower), the inflorescence stalk 0.5–1.0 cm long, densely pubescent with pustular-based, nonglandular, whitish hairs, the bract subtending each flower 2–4 mm long, lanceolate, coarsely toothed, usually shed early, the flower stalk 3–6 mm long. Calyces with the tube 0.8–1.0 mm long; the upper lip 4–5 mm long, shallowly 2-lobed apically; the lower lip 4–5 mm long, shallowly 3-lobed apically. Corollas yellow to orange, sometimes reddish- or purplish-striped or -tinged; the banner 8–9 mm long, 5–6 mm wide; the wings 7–8 mm long, 2–4 mm wide; the keel 7–8 mm long. Filaments 7–9 mm long, the tube split to slightly below the midpoint. Ovary 5–6 mm long, the style 3–5 mm long. Fruits 4–6 cm long, 4–6 mm wide, the stalk 4–6 mm long, the surfaces at maturity sparsely pustular-hairy, usually with pronounced medial lines of stout pustular-based, warty projections to 1 mm long, dehiscent into 7–12 segments, these 5–6 mm long, 5–6 mm wide. Seeds 4–5 mm long, 2–3 mm wide, reddish brown to olive brown. July–September.

Introduced, uncommon in Butler County, to be expected elsewhere in the Mississippi Lowlands Division (native of South America; introduced in the U.S. north to California, Missouri, and Pennsylvania). Rice fields and ditches.

Aeschynomene rudis was first reported for Missouri by S. Hudson (1994), who noted that it had been reported anecdotally under the name northern jointvetch as early as 1987 by the University of Missouri Agricultural Extension Service. Carulli et al. (1988) documented its distribution in the southeastern United States and contrasted it morphologically with A. indica and A. virginica (L.) Britton, Sterns & Poggenb. (with which some collections of A. rudis had been confused by earlier botanists).