Flaveria, a non-native plant, is a small, erect shrub in the Aster family. Flaveria is characterized by variable ovate to lanceolate (oval to lance shaped) leaves. The leaves have a distinctive 3-nerve pattern that gives it its specific epithet. In shaded habitat it often has soft, light green, serrate (toothed) leaves. In open habitat it is more likely to have dark, coarse leaves, often tending towards red or reddish green.
Flaveria cotyledons are ovate and lack nerves as can be seen in the following photos. The two plants in the first image were found growing in shaded conditions. In the photo on the right Flaveria (upper left) can be readily distinguished from Boerhavia repens (lower right). Note the reddish-green color of the Flaveria. Plants found on the runway can be almost completely dark reddish, with very coarse leaves, in stark contrast to leaves found in the Naupaka margin at the edges of the runway. Flaveria leaves are sessile (lacking a stem) to connate (literally joined), especially on the upper stem. Early leaves lack dentition (teeth).
These dark specimens found growing in West Turnaround RA have ovate, nerveless cotyledons. The plant below left has obvious nerves in the true leaves. In the plant below right the true leaves are too young to show nerves yet, but they will presumably grow in with time.
Description: Taprooted annual herbs 1.5-8 (-20) dm tall, puberulent or subglabrous; stems often purplish, divaricately branched. Leaves lanceolate, oblanceolate to elliptic or narrowly ovate, 3-15 cm long, (0.7-) 1-4 cm wide, distinctly 3-nerbed from base, margins subentire to serrate-dentate, petioles of principal leaves 1-2 cm long, petiole bases nearly connate, upper leaves sessile and usually connate. Heads with a single floret, aggregated into secondary head-like clusters ca. 1 cm in diameter the common receptacle thus formed with scattered bristles ca. 1/2 as long to as long as primary heads, secondary heads subtended by a few leafy bracts, heads radiate or discoid, radiate heads usually peripheral in secondary heads, the central ones usually discoid; involucre of primary heads of 1-2 bracts, 3-4.5 mm long; rays pale yellow or whitish, 0.5-1 mm long; disk corollas 2-2.5 mm long; pappus absent. Achenes 2-2.6 mm long (Wagner et al., 1999; p. 317).