A. costaricensis (Klotzsch) Duch. Slender, twining liana, conspicuously pilose on most parts. Leaves alternate; petioles slender, to 7 cm long; blades ovate, acute at apex, deeply cordate at base, 6-25 cm long, 5-15 cm wide, glabrescent above. Flowers solitary in axils, speckled white and brownish-purple; calyx expanded into a short ellipsoid balloon to 3 cm long, then constricted obliquely into a campanulate tube ca 2.5 cm long, finally opening into a narrow, fringed limb 1.5-2.5 cm long; corolla lacking; stamens 6, the anthers sessile and adnate to style; styles 6, connate; stigmas capitate. Capsules ovoid, ca 6 cm long and 4 cm wide, dehiscing from base, bearing many seeds; seeds disk-shaped, ca 1 cm diam. Croat 9011. Occasional, around the Laboratory Clearing. Flowers mostly from January to May, sometimes later in the rainy season also. The fruits have not been seen on the island.