C. panamensis Cook Rubber tree, Mastate blanco, Caucho, Hule, Ule Monoecious or dioecious tree, 10-30 m tall, with low buttresses; young parts densely yellowish-pubescent; stems hollow; sap white. Leaves pendulous, deciduous; petioles to 1 cm long; stipules fully amplexicaul, 3-9 cm long, densely golden, appressed-pubescent, deciduous; blades oblong to oblong-obovate, acuminate at apex, cordate at base, 20-45 (55) cm long, 8-18 (25) cm wide, minutely ciliate-denticulate, asperous especially below with short, spreading, often golden trichomes. Flowers inserted on large, flattened, unisexual receptacles covered with imbricate bracts, the receptacles axillary or at defoliated nodes, involucrate; primary staminate inflorescences (2) 4 (6) per axil, fan-shaped, conduplicate, to 15 mm long and 25 mm wide; peduncles 3-10 mm long; bracts in 10-12 series; perianth absent; stamens numerous, scattered among the bractlets; filaments to 3.5 mm long; anthers oval, ca 1 mm long; complemental staminate inflorescences (accompanying pistillate inflorescences) usually 2, similar to primary ones or funnel-shaped to cup-shaped. Pistillate receptacles usually solitary, thickly discoid, 1-2 cm diam, 1-2 cm thick, nearly sessile; involucral bracts in 5-10 series; flowers mostly 15-30; perianth tubular, (1.5) 2-3 mm long, shallowly 4 (5)-lobed, fleshy, short-velutinous, accrescent; ovary subinferior; styles dimorphic, to 1.5 mm long with stigmas 3-6 mm long or 2-3 mm long with stigmas less than 3 mm long; stigmas 2, rarely 3. Fruits thick, discoid syncarps 2.5-4.5 cm wide; seeds many, ca 1 cm long and enclosed in the orange, fleshy, accrescent perianth. Croat 5335. Occasional in the forest on the western side of the island. Probably flowers in the late dry and early rainy seasons (April and May). Berg (1972) reported that the species flowers all year. The fruits are mature in May and June. The leaves are lost in the dry season.