RUBIACEAE  

Unarmed trees; branches glabrous. Leaves paired, petiolate, large, ovate or broadly elliptic; stipules large, elliptic to broadly obovate, deciduous. Inflorescences globose, solitary, terminal, with flowers very densely crowded on a +/- globose, fleshy, +/- pilose receptacle; interfloral bracteoles absent. Calyx 5-lobed, lobes free, linear-spathulate, persistent. Corolla +/- tubular; lobes 5, imbricate. Stamens: filaments very short; anthers 2-thecous. Ovaries closely contiguous but not fused, each 2-locular; locules with many ovules, placentas attached to middle of septum; style slender, exserted; stigma red, narrowly conical with widened base and blunt tip, sulcate. Fruiting heads globose, but individual fruits not joined, red, irregularly breaking, crowned by persistent calyx lobes. Seeds not winged, but sometimes angular; testa reticulate; embryo straight, surrounded by albumen.

Small trees or shrubs, rarely lianas. Leaves shortly petiolate; petioles normally channelled above; blades thin or scarcely coriaceous, mid- and lateral nerves usually prominent beneath; stipules persistent, usually connate above nodes for a short distance. Flowers moderate in size or small, borne in terminal, spicate thyrsoid panicles, scorpioid cymes or spherical compact heads. Calyx with limb produced above tube, cup-shaped and frequently wider than tube, truncate or 5-toothed or -lobed. Corolla with hairy throat, often with walls of tube toughened or thick; tube exceeding calyx-limb; lobes (4)5, usually acuminate or apiculate, contorted in bud. Stamens: anthers (4)5, subsessile, attached by very short filaments near base, included, linear, sagittate or bilobed at base, connective extended into an apiculate apex. Disc glabrous, fleshy, cup-shaped, or annular. Ovary 2-locular with numerous ovules inserted on a thickened placenta; stigma borne on style +/- club-shaped, formed from 2 flattened appressed branches (seldom separating), with 10 membranous linear vanes which fit between anthers in bud. Fruit indehiscent, ovoid or globose, often coriaceous; calyx persistent; pedicels sometimes accrescent. Seeds many, red-brown to black, angular, rugulose or granulose.

Subshrubs with many branches from a thick woody rootstock, often tufted. Leaves opposite but sometimes appearing verticillate, linear to ovate; stipules with 3-5 short lobes from a short base. Flowers heterostylous, solitary or paired, axillary or at apices of branchlets. Calyx: tube ovoid; lobes unequal, one foliaceous and rest minute or of varying sizes. Corolla: tube filiform, enlarged at apex; throat hairy inside; lobes 5, ovate. Stamens 5, included or exserted. Ovary 2-locular with many ovules; style included or exserted; stigma lobes filiform. Capsule ovoid, splitting into 2 cocci. Seeds many; testa finely striate.

Tall lianes with flexible stems. Leaves petiolate, ovate, symmetrical, acuminate, base rounded to cordate, with 4-6(7) arcuate-ascending secondary nerves on each side of midrib, puberulous on midrib and nerves beneath; axillary domatia with a small rounded, ciliate opening; interpetiolar stipules small, apiculate, fused into a short tube at base. Inflorescences terminal, +/- contracted cymes on lateral branches; floral buds elongate, subacute. Flowers bisexual or male, protandrous. Calyx tubular with 5 pointed lobes. Corolla campanulate; lobes 5, ovate, contorted in bud. Stamens arising on lower half of corolla tube; filaments very short, attached to lower 1/4 of anther; anthers with or without pollen; connective prolonged beyond thecae; pollen in tedrads. Disc annular. Ovary 2-locular; ovules many, axile; style slender in basal part, then swollen and furrowed in upper 3/4; stigma 2-lobed, purple, not opening and spreading when non-functional. Fruit barrel-shaped with a long peduncle, smooth when ripe, solitary or few in an infructescence; exocarp subcoriaceous; seeds embedded in soft, juicy pulp. Seeds many, slightly angular; endosperm present; embryo straight with rounded cotyledons.

Trees or lianas, sometimes shrubby; younger parts with silky or tomentose indumentum; twigs terete, often hollow. Leaves decussate, shortly petiolate, oblong to obovate, often unequal at base, hirsute, especially on nerves; tuft-domatia in axis of secondary and tertiary nerves; mesophyll containing crystal stars visible as very small dots; stipules interpetiolar, shortly connate at base, deciduous, leaving a ring of hairs on scar. Inflorescence terminal, pseudoaxillary, many-flowered, shortly pedunculate, erect, rarely ramiflorous. Flowers bisexual. Calyx cupular to tubular, with 5, short to long teeth, silky inside and outside; colleters present on inside. Corolla: tube shortly cylindrical in lower part, campanulate in upper part, silky outside except area at base, glabrous inside except 5 hair tufts in basal part; lobes 5, contorted to right, ovate to circular. Stamens 5, included in upper part of tube; filaments very short; anthers infra-medifixed, connective containing tannin cells. Ovary 2-locular; placentation axile, placenta T-shaped in cross section; ovules many, arranged all around placenta; style somewhat shorter than tube, cylindric with 10 longitudinal grooves, thickened at top into a club-shaped stigma. Disc cylindric, 5-lobed, often sparsely hispid on upper surface. Fruit 2-locular, narrowly or broadly ellipsoid, ribbed and often wrinkled between ribs, crowned with persistent calyx; pericarp fleshy, containing stony strings; endocarp thin. Seeds many, irregularly angular; hilum small, comma-shaped; embryo straight.