Anthurium marcusianum Théofilo, L.Kollmann & Sakur.

Rupicolous herb; stem elongate, . 5 cm, erect; internodes 0.3–0.5 cm; prophylls and cataphylls 2.2–7.3 cm, greenish when young, brownish to chestnut when old, drying medium brown, persistent and entire at the stem apex, persistent at the stem base; sheath 2.1–2.9 cm. Leaf not peltate; petiole 14.3–18.1 3 0.4–0.5 cm, erect, greenish, covered with raphide cells, without glandular punctations, terete; geniculum 0.5–0.8 cm, clear matte green when fresh, drying blacker than the rest of the petiole, terete, without glandular punctations; leaf blade 8.2–18.8 3 7.5–20.3 cm, perpendicular to petiole, ovate, chartaceous when fresh, coriaceous when dry; upper surface green, with whitish border, drying medium green, densely covered with raphide cells, lower surface light green, matte, drying medium green, without glandular punctations; apex acute; base cordate; anterior lobe 8.2–12 cm; posterior lobes 4.1–9.1 cm, imbricate to not imbricate, rounded at apex; sinus spathulate to obovate; midrib whitish adaxially, obtuse at the base, rounded and prominent at the apex adaxially, rounded and prominent abaxially; basal veins 4 to 5 pairs; 1st pair free to the base or fused for 0.73–1.24 cm, reaching the apex or the margin above 1/2 of the anterior lobe length; 2nd pair of basal veins fused for 2.33–3 cm, reaching the margin above 1/3 to 2/3 of the anterior lobe length; 3rd and 4th pairs of basal veins fused for 1.07–4.34 cm, reaching the margin of the posterior lobe, 5th pair of basal veins free to the base or fused to 1.6 cm, reaching the margin of the posterior lobe; primary lateral veins 6 to 9 on both sides, arched, prominent adaxially when fresh, raised below abaxially when fresh; interprimary veins distinct from the primary lateral veins; collective vein arising from the base, 0.4–2 cm from the margin. Peduncle 24.5–40.1 3 0.4 cm, 1.7–2.7 times longer than the petiole, erect, terete, greenish, glandular punctations absent, covered with raphide cells, geniculum absent at the apex; spathe 4.2–6.1 3 0.6–0.8 cm, chartaceous when fresh, expanded, coriaceous when dry, greenish, lanceolate, decurrent at base, forming obtuse to right angle with the peduncle, rostrate to acuminate at apex, reflexed until post-anthesis, pustules absent, both surfaces densely covered with white speckles; spadix 4.6–6.5 3 0.4–0.5 cm, sessile, tapered, purplish in preanthesis, brownish to pale green in post-anthesis; 4 to 5 flowers visible per principal spiral, 5 flowers visible per secondary spiral. Flowers rhombic; tepals purplish until anthesis, purplish at the apex, becoming whitish toward the base post-anthesis, dorsally acute, internally convex; lateral tepals 1–1.23 3 0.87–0.92 mm; anterior/posterior tepals 1.23–1.28 3 0.58–0.59 mm; stamens emerging in a scattered manner, laterals first, followed quickly by alternates; filaments flattened, striated, 1.56–1.59 3 0.20–0.25 mm; anthers 0.32–0.5 3 0.25–0.29 mm, dorsifixed, extrorse; pistils purplish, oblong, not emergent; stigma sessile, rounded; ovary 0.99–1.32 3 0.46–0.53 mm, bilocular, 1 ovule per locule, axial placentation; funicle with trichomes. Infructescence not seen.