Isertia laevis (Triana) B. M. Boom

Cassupa panamensis Standley, Contr. U. S. Nat Herb. 18: 135. 1916.
Branchlets densely short-pilose or tomentose with fulvous hairs; stipules triangular, 10-12 mm. long, acuminate, thick; petioles stout, 3-6.5 cm. long, cinereo-puberulent; leafblades oval or broadly oval, 26-34 cm. long, 12-17 cm. wide, rounded or obtuse at the base and abruptly decurrent, cuspidate-acuminate at the apex, with an acute acumen 2.5-3 cm. long, brightgreen above, lustrous, puberulent along the veins, elsewhere glabrous, the venation impressed, whitish beneath with a fine close tomentum, puberulent along the veins, the lateral veins prominent, 18-20 on each side, straight, divergent, arcuately anastomosing near the margin, the secondary veins prominently reticulate; inflorescence many-flowered, 15-19 cm. long, 11 cm. wide, the peduncle 5 cm. long, the flowers partly sessile and partly on stout compressed pedicels 5-10 mm. long; hypanthium 4-5 mm. long, the calyx about 1 mm. long, ciliolate; corolla white, the tube 5.2 cm. long, dilated above, finely tuberculate, sparsely puberulent, the lobes oblong, 11 mm. long, 4.5 mm. wide or narrower, obtuse or acute; filaments 3 mm. long, the anthers 9 mm. long; style 3.2 cm. long, puberulent; fruit subglobose, 1 cm. long (immature), glabrous; seeds about 1 mm. long, foveolate.
Type locality: Along the Rio Fat6, Province of Colon, Panama, altitude 10 to 100 meters. Distribution: Known only from the type locality.