Shrubs and trees, unarmed, terrestrial, without raphides in the tissues, often with well developsed hirsute or strigose pubescence. Leaves opposite or verticillate, subsssile or petiolate, with tertiary and quaternary venation not lineolate, without domatia; stipules caducous, fused into a calyptrate cap, splitting along 1--2 sides. Inflorescences terminal, cymose to thyrsiform, multiflowered, pedunculate or subsessile and tripartite, bracteate. Flowers sessile to pedicellate, bisexual, homostylous, protandrous, fragrant, apparently diurnal; hypanthium obconic to  turbinate; calyx limb developed, calyptrate and splitting irregularly or open, truncate to regularly 4--5-dentate, and sometimes with calycophylls; corolla funnelform to campanulate or tubular, white to pale green or flushed with pink or purple, internally glabrous except with tufted pubescence at stamen insertion that produces a barbate throat, lobes 5, triangular to ligulate, in bud convolute, without appendage; stamens 5, inserted in upper part of corolla tube, anthers narrowly ellipsoid-oblong, dorsifixed, opening by longitudinal slits, exserted, with apical appendage; ovary 2-locular, ovules numerous in each locule, on axile placentas, stigmas 2, ellipsoid to ligulate, exserted. Fruit capsular, subglobose to turbinate, loculiciidally dehiscent across apex, woody to chartaceous, smooth, with calyx limb persistent; seeds numerous, angled, small (0.2--0.5 mm), sometimes thinly winged, seed surface striate to foveolate, wing when present entire. 

Key to Species of Schizocalyx; based on Taylor et al. 2011

1. Calyx limb 6-12 mm long, more than 6 mm long on at least sme flowers; corolla lobes 6-10 mm long.

    2. Leaves subsessile to shortly petiolate, petioles up to 5 mm long; inflorescences congested to subcapitate, flowers subsessile or on pedicels up to 5 mm long.....Schizocalyx multiflora

    2' Leaves petiolate, petioles 4-20 m long; inflorescences lax, flowers all on pedicels 1-20 mm long, and more than 5 mm long on at least some flowers....Schizocalyx sterculioides

1'. Calyx limb 1-7 mm long, on most flowers less than 6 mm long; corolla lobes 2.5-6 mm long.

        3. One or more flowers on an inflorescence with a petaloid white calycophyll (this sometimes deciduous after anthess); corolla tube more than 2 times as long as the lobes, the tube 7-8 mm long and the lobes 1.5-3.5 mm long... Schizocalyx bracteosus

        3'. Flowers and inflorescences without calycophylls; corolla tube shorter than, equal to, or up to 2 times as long as the lobes, the tube 1-6 mm long and the lobes 3-9 mm long.

            4. Calyx limb fully fused and calyptrate in bud, as corolla expands splitting irregularly or sometimes more or less regularly, with lobes or segments 0.6-3.5 mm long.

                 5. Flowers arranged in congested to subcapitate groups, all subsessile to shortly pedicellate, the pedicels up to 1 mm long in flower (but sometimes elongating in fruit); calyx becoming regularly to irregularly lobed...... Schizocalyx peruvianus

                 5'. Flowers arranged in rather lax cymes, each cyme with some flowers sessile to subsessile and some pedicellate, the pedicels up to 15 mm long; calyx becoming irregularly lobed or split.

                        6. Pedicels 2-15 mm long; capsules 10-15 x 5-6 mm; Costa Rica and Panama.... Schizocalyx veraguensis

                        6'. Pedicels 0.5--6 mm long; capsules 2-4 x 2.--4 mm; Colombia, Ecuador, and Peru.

                              7. Leaves opposite or more often ternate; leaf blades 10.5-28 x 5-16 cm; corolla with tube 4.5--5 mm long and lobes 4--5 mm long; Ecuador and Peru....Schizocalyx condoricus

                              7'. Leaves opposite; leaf blades 5-10.5 x1.8-3.5 cm; corolla with tube 5--8 mm long and lobes ca. 3 mm long; northern Colombia....Schizocalyx magdalenae

            4. Calyx limb open or with imbricated lobes in bud, truncate or regularly denticulate with teeth up to 0.4 mm long, the calyx limb sometimes tardily elongating and splitting in fruit.

                   8. Corolla with tube 5--6 mm long and the lobes 4.5--6 mm long and generally about as long as tube; plants of Bolivia.... Schizocalyx magnorum

                   8. Corolla with tube 1-4 mm long and the lobes 1.5-9 mm long and generally longer than tube; plants found widely in Brazil and western South America.

                        9. Corolla lobes 6-9 mm long; plants of southeastern Brazil.... Schizocalyx cuspidatus

                        9'. Corolla lobes 1.5-4.5 mm long; plants of western South America.

                            10. Calyx limb ca. 1.5 mm long; corolla tube 3-4 mm long......Schizocalyx obovatus

                            10'. Calyx limb 0.2--0.5 mm long; corolla tube ca. 1 mm long.

                                  11. Corolla lobes ca. 2.5 mm long; capsules 3 x 3-4 mm; plants of northwestern Ecuador.....Schizocalyx ecuadorensis

                                  11'. Corolla lobes 4--4.5 mm long; capsules 4-4.5 x 4 mm; plants of Central Peru.....Schizocalyx truncatus