LEAVES erect; petioles 2-16 cm long, more or less quadrangular, broadly sulcate, 3-ribbed abaxially; geniculum 1-2 cm long; blades oblanceolate to narrowly obovate, coriaceous, acuminate or acute at apex, acute to narrowly rounded or weakly lobed at base, 30-108 cm long, 13-36 cm wide, broadest above the middle; both surfaces semiglossy; midrib flat at base above, becoming acutely raised toward middle, sunken at apex, 3-ribbed at base below, becoming acutely raised toward apex; primary lateral veins 10-17 per side, departing midrib at 50-65° angle, raised on both surfaces; collective vein arising from one of the primary lateral veins in apical one-fourth of blade, 5-10 mm from margin.

INFLORESCENCE arching-erect to spreading; peduncle 30-75 cm long, 5-9 mm diam., usually subterete, sometimes singularly ribbed; spathe moderately thick, green tinged with violet purple, narrowly oblong-ovate or oblong-elliptic, 5.5-9.5 cm long, 2.1-3.5 cm wide, gradually to abruptly acuminate at apex, acute to obtuse at base, inserted at 10-70° angle; spadix dark purple-violet, becoming brown, 5.7-16 cm long, 8-12 mm diam. near base, 7-9 mm diam. near apex; flowers rhombic, 2-3.3 mm long, 2.4-3.5 mm wide, the sides more or less straight parallel to spirals, sigmoid perpendicular to spiral; 7-9 flowers visible in the principal spiral, 6-10 flowers visible in the alternate spiral; tepals matte to semiglossy; weakly to conspicuously, densely punctate, forming large nectar droplets on surface at anthesis; lateral tepals 2-2.3 mm wide, the inner margins straight; pistils weakly emergent, green tinged violet purple to violet purple; stigmas broadly elliptic, brushlike, weakly exserted, with droplets 5-8 days before stamens emerge; stamens emerging rapidly in a scattered manner throughout, sometimes those at apex emerging first; anthers purplish brown to purple-violet, 0.8-1 mm long, 0.8-1.1 mm wide, held above tepals in tight cluster obscuring pistil; thecae oblong-elliptic, more or less divaricate; pollen purplish (B & K Purple 6/10).

INFRUCTESCENCE pendent, the spadix to 30 cm long, 2.5 cm diam.; berries obovoid, red, 7-8 mm long; mesocarp transparent, gelatinous; seeds 2, oblong-elliptic, white, ca. 4 mm long. Figs. 43 and 44.

The species is known from central Panama on the Atlantic slope ranging to northern Colombia from sea level to 100 m in tropical wet forest and wetter parts of tropical moist forest. It is expected in Costa Rica in Lim—n Province. The species is in section Pachyneurium. Although its leaves are typical for that section, it differs from other members of the section by its short, cylindrical, violet purple spadix that is held erect at anthesis and by its tendency to form globular droplets on its tepals. Also characteristic of this species are its purplish pollen, its bright red berries, and its petioles that are broadly sulcate adaxially and usually prominently three-ribbed abaxially.

Anthurium concolor is not closely related to any other species but has been confused with A. salviniae because of its similar leaves, habit, and infructescence. Due to similar leaf shape and petiole shape, the species could also be confused with A. upalaense Croat & Baker, but that species has a long-tapered inflorescence at anthesis.

Map of Mesoamerican specimens with coordinates

Panama Bocas del Toro:, , Carleton 377 (US).
Panama Canal Area: < 25 m, 09.19.00N 79.57.30W, 20 June 1994, Thomas B. Croat & Guanghua Zhu 76286 (MO).
Panama Canal Area: Barro Colorado Island,, , Croat 8154 (MO).
Panama Canal Area: Río Providencia,, , Tyson & Blum 3999 (SCZ).
Panama Canal Area: Río Providencia,, , Tyson & Blum 3936 (MO).
Panama Canal Area:, , Standley 28723 (US).
Panama Canal Area:, , Standley 31018 (US).
Panama Canal Area:, , Cowell 324 (NY).
Panama Chiriquí: Portobelo Region, 0-300 m,, , Pittier 2798 (US).
Panama Col—n:, 25 Nov. 1978, Thomas B. Croat 50108 (Cult) (B,BM,CAS,CM,DUKE,F,GH,MICH,MO,PMA,RSA,S,SEL,US,VEN).
Panama Col—n: Portobelo Region,, , Thomas B. Croat 33637 (B, F, K, MO, PMA, RSA, U, US).

South American Specimens Colombia Choco: 0-100 m,, 19 January 1981, D'Arcy 14217 (MO).