Anthurium palenquense Croat

Terrestrial; stem green turning brown, calloused, 15–30 cm long, 1–2.5 cm diam.; leaf scars obscured by root mass, 1 cm high, 1–1.5 cm wide; roots numerous, descending, grayish or green, smooth or scurfy, blunt, 1–20 cm long, 2–5 mm diam.; cataphylls membranous to subcoriaceous, lanceolate, 4.5–17 cm long, narrowly acute and apiculate at apex, green tinged reddish at margins, drying pale tan (B & K yellow 5/10), persisting semi-intact or as coarse linear fibers or as bundles of linear fibers, often with the apex remaining intact. Leaves erect to spreading; petioles (6)10–30 cm long, 5–20 mm diam., sharply triangular, flattened to broadly convex adaxially, the margins winged, sharply angular abaxially; geniculum scarcely thicker and slightly paler than petiole, the angular ribs often conspicuously and minutely undulate, 1–3 cm long; sheath 1–2 cm long; blades subcoriaceous to coriaceous, elliptic to lanceolate or oblanceolate, long-acuminate at apex (the acumen flat to slightly inrolled), attenuate with conspicuously concave margins at base, (16)30–64(70) cm long, (7.5)10–23 cm wide, broadest usually near or below the middle, the margins broadly undulate; upper surface matte, velvety, the cells convex, sunken, forming an alveolate pattern when dried, dark green (B & K green 4/2.5), lower surface matte, paler (B & K green 7/2.5); midrib flat to obtusely angular at base, becoming sharply acutely raised toward the apex above, acutely raised, (knife-edged) and higher than broad below; primary lateral veins (9)14–30 per side, departing midrib at 40–65(80) degree angle, ascending straight to the collective vein, weakly sunken to weakly raised above, darker than surface and weakly raised below; interprimary veins numerous, scarcely sunken, more or less parallel to and less conspicuous than primary lateral veins; tertiary veins obscure above and below; collective vein arising from near the base, weakly sunken or weakly raised above, weakly raised or flat below, prominulous when dried, equally as prominent as primary lateral veins, 5–18 mm from margin. Inflorescences erect to slightly spreading or more or less pendent, shorter than leaves; peduncle 10–60 cm long, 2–10 mm diam., 0.3–3 times as long as petiole, green to dark purple or heavily tinged-mottled with red-purple (B & K red-purple 2/2.5), more or less quadrangular or with 2–4 irregular ribs and convex sides; spathe spreading and weakly twisted or reflexed, membranous to subcoriaceous, green tinged maroon at margins and along main nerves (B & K red-purple 2/10), minutely pale-speckled (at least abaxially), narrowly lanceolate to oblong-lanceolate, 3–12 cm long, 0.5–2.5 cm wide, broadest near base, inserted at 30–90 degree angle on peduncle, acuminate at apex (the acumen inrolled, (2)5–15 mm long), acute to decurrent at base; stipe 3–15 mm long in front, 1–5 mm long in back; spadix yellow-green tinged with purple, becoming purple-violet or dark green tinged purplish at anthesis, cylindroid, sometimes weakly tapered, erect to curved, (2)4–12 cm long, 3–5 mm diam. near base, 3–4 mm diam. near apex; flowers with a faint, sweet, fruity scent, square to rhombic, 2–3.8 mm long, 1–3.8 mm wide, the sides straight to gradually sigmoid; 2–5 flowers visible in principal spiral, 2–6 in alternate spiral; tepals matte to semiglossy, minutely papillate and weakly punctate; lateral tepals 1.4–2.6 mm wide, the inner margins broadly convex, turned up against pistil, the outer margins 2-sided; pistils exserted 0.4–1.5 mm, glossy, green, sometimes tinged with purple around the stigma; stigma ellipsoid, greenish, 0.4–0.8 mm long, 0.25–0.4 mm wide, brush-like with blunt papillae, droplets appearing 1 week before stamens emerge; stamens emerging rapidly in a regular sequence from the base, the laterals preceding the alternates by 5–28 spirals (by ca. 3/4 the length of the spadix), held erect above tepals and pistil; filaments translucent, exserted, 0.6–1 mm long, 0.4 mm wide; anthers orange (B & K yellow-red 7/10), 0.4–0.6 mm long, 0.5–0.7 mm wide, not obscuring pistil; thecae ellipsoid, 0.25 mm wide, weakly divaricate; pollen orange to yellow fading to cream-white (B & K yellow-red 7/2.5). Infructescence with spathe persisting; spadix 5–15 cm long, 0.5–1.5 cm diam.; berries dark purple, ovoid, acute at apex, 5–11 mm long, 5–6 mm diam.; pericarp thickened, with numerous raphide cells; seeds 1–2 per berry, with numerous raphide cells, rounded to ovoid, usually flattened on one side, 4–5.6 mm long, 3.2–3.8 mm diam., 1–2.8 mm thick, with a translucent gelatinous appendage at both ends.

A member of series Multinervii, Anthurium palenquense occurs in Ecuador in Esmeraldas, Cotopaxi, Los Ríos, Morona-Santiago, and Pichincha provinces, at 80 to 400 m, typically in mature forest or in disturbed primary forest in tropical moist and premontane wet forest life zones. Most collections were made at the Río Palenque Biological Station in Los Ríos, hence the name. Anthurium palenquense is distinguished by its terrestrial habit, coarse cataphyll fibers, triangular﷓winged petioles and closely veined, bicolorous blades which are attenuate at the base and matte to semi﷓velvety on the upper surface. In addition, the long﷓exserted stamens and the brush﷓like stigma are characteristic. An unusual feature is the pale raphide cells speckling the petioles, spathe, tepals and even the filaments, as well as the pericarp and seed coat. This species (erronously reported as A. buenaventurae Engl.) is pollinated by Eulaema bomboides (Dodson & Gentry, 1978). Two collections of Anthurium palenquense from Esmeraldas and Cotopaxi (Asplund 16306 and Sparre 17214), do not display the brush﷓like stigma (typical of the species), but agree in other characters with the present overall concept of A. palenquense. Anthurium palenquense is most closely related to A. napaeum, which differs in having the leaf blades mostly acute at the base with convex to more or less straight (rather than concave) margins.

Anthurium palenquense is a species of plant in the family Araceae. It is endemic to Ecuador. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane forests. It is threatened by habitat loss.