Trees, shrubs, annual or perennial herbs, subshrubs, vines, or lianas, infrequently monocaulous or creeping and rooting at nodes, terrestrial or infrequently epiphytic, with bisexual flowers, infrequently dioecious, or rarely polygamo-dioecious (Diplospora, Galium, Guettarda, perhaps Brachytome) or monoecious (Galium), evergreen or sometimes deciduous (Hymenodictyon), sometimes armed with straight to curved spines (formed by modified stems or peduncles), infrequently with elongated principal stems bearing lateral short shoots (i.e., brachyblasts; Benkara, Catunaregam, Ceriscoides, Himalrandia, Leptodermis, Serissa), infrequently with lateral branches or short shoots spinescent (i.e., prolonged, sharp, and leafless at apex), infrequently with reduced internodes that give an appearance of verticillate leaf arrangement (Brachytome, Damnacanthus, Duperrea, Rothmannia, Rubovietnamia), infrequently with buds resinous (Gardenia) or mucilaginous (Scyphiphora), infrequently with tissues fetid when bruised, [rarely with swollen hollow stems or leaf bases housing ants (Neonauclea)]; branchlets terete to angled or quadrate, in latter two cases often becoming terete with age, or rarely flattened (Wendlandia) or winged (Hedyotis, Rubia), buds conical or rounded with stipules valvate or imbricate, or infrequently flattened with stipules erect and pressed together (Cinchona, Haldina, Nauclea, Neonauclea). Raphides present or absent. Leaves opposite, verticillate, or apparently verticillate (i.e., closely set due to reduced internodes), decussate or occasionally distichous, petiolate to sessile, infrequently somewhat to strongly anisophyllous, rarely punctate- or striate-glandular (Galium); margins flat to occasionally undulate or crisped, entire or rarely lobed (Hymenodictyon, Morinda) to denticulate or serrate (Hymenodictyon, Leptomischus, Ophiorrhiza, Wendlandia); secondary veins pinnate or rarely triplinerved or palmate (Hedyotis, Rubia), free (i.e., eucamptodromous) or uniting near margins (i.e., brochidodromous) in weak to well-developed or rarely substraight submarginal vein, sometimes with foveolate (i.e., pitted or cryptlike) and/or tufted (i.e., pubescent) domatia (i.e., structures that house mites) in abaxial axils, these rarely also present in axils of tertiary veins (Morinda), with presence of domatia often variable within a species; tertiary and/or quaternary venation rarely arranged in regular squares (Guettarda), regular rectangles (i.e., clathrate; Urophyllum), or lineolate (i.e., closely parallel within each areole; Timonius); petiole rarely articulate at base (Ixora); stipules persistent with leaves, deciduous before leaves, or quickly caducous, interpetiolar and infrequently fused to adjacent petioles or leaf bases, sometimes united around stem into a sheath, rarely completely united into a conical cap (i.e., calyptrate; Gardenia), with interpetiolar portion variously triangular in general shape to truncate, with apex entire or bilobed, multifid, lacerate, setose, or laterally appendaged, with apex, lobes, setae, and/or appendages sometimes glandular (Chassalia, Hedyotis, Hymenodictyon, Knoxia, Mitchella, Mycetia, Neanotis, Ophiorrhiza, Pentas, Pseudopyxis, Psychotria, Trailliaedoxa), internally (i.e., adaxially) with small to well-developed colleters (i.e., glandular trichomes), these infrequently persistent after stipules fall (Psychotria), or stipules rarely expanded into 1 to several leaflike segments and then apparently absent due to leaflike form that gives an appearance of verticillate leaves (Argostemma, Asperula, Galium, Microphysa, Phuopsis, Rubia). Inflorescences terminal, axillary (i.e., borne at both axils at a node), or pseudoaxillary (i.e., borne consistently in 1 axil per node; lateral), sometimes apparently leaf-opposed due to marked anisophylly, or rarely superaxillary (Damnacanthus, Diplospora) or cauline (Mycetia), variously cymose to thyrsiform, corymbiform, paniculiform, racemiform, spiciform, fasciculate, or capitate and few to many flowered or occasionally reduced to a solitary flower, pedunculate (peduncle here used for basalmost axis supporting inflorescence or solitary flower) to sessile, when sessile often with 3 principal axes (i.e., tripartite), bracteate or bracts sometimes reduced or apparently absent, with bracts (here usually including bracts borne on pedicels or next to flowers, i.e., bracteoles) generally triangular to linear or sometimes leaflike (i.e., similar to normal or somewhat reduced leaves) and rarely enlarged, petaloid, and resembling calycophylls (Dunnia, Neohymenopogon), infrequently fused and involucral, occasionally fused in pairs (i.e., forming a calyculus, or calyculate), infrequently thickened and spatulate to clavate or conical (genera of Naucleeae), or infrequently stipuliform, rarely glandular (Damnacanthus, Mycetia), multifid to fimbriate (Damnacanthus, Kelloggia, Spermacoce) or spinescent (Phuopsis). Flowers sessile to pedicellate (pedicel here used for ultimate axis immediately supporting a single flower, except when this is a peduncle), bisexual and monomorphic, distylous, or rarely tristylous (Chassalia, Pentas), unisexual with 2 forms generally similar except for corolla size and hypanthium development, or rarely cleistogamous (Ophiorrhiza), actinomorphic or rarely zygomorphic (Argostemma), sometimes with ovaries of individual flowers partially to fully fused (Mitchella, Morinda, Mouretia, Nauclea), variously diurnal or nocturnal, usually sweetly fragrant, protandrous [or rarely protogynous], occasionally with secondary pollen presentation (e.g., Ixora, Pavetta, Phuopsis, Scyphiphora, genera of Naucleeae). Calyx gamosepalous and fused to inferior ovary in hypanthium or ovary portion, this generally ellipsoid, turbinate, obconic, cylindrical, or occasionally subglobose to hemispherical, glabrous and smooth, pubescent, or rarely tuberculate (Galium) or with unusual flattened (Dentella) or hooked, sometimes glandular trichomes (Galium, Kelloggia), or rarely longitudinally ridged to winged (Gardenia,Spiradiclis), above this developed into a free limb portion, this limb variously tubular to cupular or infrequently reduced to obsolete (Asperula, Coffea, Galium, Leptunis, Microphysa, Ophiorrhiza, Phuopsis, Rubia), truncate to 4- or 5(-9)-denticulate (i.e., lobes reduced to tiny projections along a generally truncate margin) or shallowly to deeply 4- or 5(-9)-lobed, open in bud or rarely with lobes markedly imbricate (Emmenopterys, Keenania), [or rarely spathaceous (i.e., fused into a conical cap that splits irregularly)], inside variously near base and/or at sinuses between lobes with few to numerous small colleters, rarely densely or markedly veined (Clarkella, Myrioneuron, Pseudopyxis), rarely on margins with well-developed, sessile to stalked glands (Mycetia), lobes generally triangular to linear, occasionally obtuse to lanceolate or oblanceolate, or rarely prolonged into a slender shaft bearing a thickened apical portion (Neonauclea), occasionally slightly to markedly unequal on an individual flower with all lobes of different lengths or infrequently in unequal pairs of similar lengths (Diodia, Mitracarpus, Spermacoce), infrequently with 1(to 5, Mussaenda) lobe on some (or all, Mussaenda) flowers of an inflorescence enlarged into a calycophyll (i.e., a membranous to papery, petaloid, veined, white to colored blade borne on a generally well-developed stipe; Emmenopterys, Morinda, Mussaenda, Schizomussaenda). Corolla large and often showy to reduced, gamopetalous, white, yellow, orange, red, blue, purple, and/or pale green, when nocturnal often white at anthesis becoming yellow with age, variously funnelform, salverform (i.e., hypocrateriform), tubular, campanulate, or occasionally rotate to infrequently urceolate (i.e., swollen in basal part of tube; Canthium, Lasianthus) or inflated (i.e., markedly swollen in middle or upper part of tube; Keenania, Leptomischus), infrequently curved in tube and/or gibbous (i.e., asymmetrically swollen at very base of tube; Chassalia, Guettarda, Mycetia, Ophiorrhiza), infrequently differing in shape between long-styled and short-styled forms (Antirhea), infrequently markedly fleshy to leathery (Caelospermum, Damnacanthus, Fosbergia, Rothmannia, Timonius, Urophyllum), inside glabrous to variously pubescent with pubescence frequently confined to throat, outside infrequently ridged to winged (Cinchona, Ophiorrhiza), rarely fenestrate in tube (i.e., with longitudinal slits; Damnacanthus, Paederia), lobes (3 or)4 or 5(-11), shorter than or occasionally longer than tube, acute or less often obtuse to rounded at apex, generally spreading to somewhat reflexed at anthesis, infrequently with margins crisped to irregular, densely ciliate, and/or appendaged (Cinchona, Luculia, Rondeletia, Saprosma, Serissa), in bud imbricate (and usually quincuncial), valvate, valvate-induplicate, valvate-reduplicate, or convolute (i.e., contorted) to left or rarely to right (Coptosapelta, Rothmannia), usually with aestivation consistent within a genus, occasionally with wings, ridges, and/or rounded to hornlike thickenings or protuberances on back or at apex (Lerchea, Ophiorrhiza), rarely cucullate (Lerchea). Stamens adnate to corolla, free or rarely fused to stigma (Acranthera), alternate to corolla lobes and isomerous (i.e., equal in number to lobes) or rarely more numerous (Gardenia) [to rarely fewer], inserted variously in corolla throat, tube, or infrequently at base and sometimes appearing free (Galium), included to exserted, with point of insertion and position of anthers usually differing between long-styled and short-styled forms of distylous flowers, with staminodes of pistillate flowers generally similar to stamens but smaller; filaments well developed to reduced or obsolete, free or rarely coherent (Argostemma) or fused (Acranthera, Argostemma), variously glabrous to pubescent, occasionally markedly flattened (Hymenodictyon, Kelloggia); anthers free or rarely coherent or fused (Argostemma), 4-thecal or rarely 2-thecal (Hymenodictyon), 2-celled, in outline generally narrowly oblong, linear (i.e., narrowly fusiform), narrowly lanceolate, or narrowly elliptic, at base occasionally bifid (i.e., sagittate; Caelospermum, Cephalanthus, Duperrea, Hamelia, Neohymenopogon, Scyphiphora), dorsifixed (i.e., medifixed to dorsifixed near base) to occasionally basifixed, infrequently pubescent (Hyptianthera, Lerchea), with dehiscence introrse by longitudinal slits or rarely by apical pores (Argostemma), with connective infrequently prolonged into an apical and/or sometimes basal appendage (Acranthera, Argostemma, Hyptianthera, Morinda, Rubovietnamia, Wendlandia), appendages rarely fused into a cone (Acranthera); pollen variously 3- or 4(or 5)-colpate and generally subglobose or occasionally 3- or 4-porate, 5-25-colpate and disk-shaped or ellipsoidal, in tetrahedral tetrads and 3- or 4-porate, cylindrical with 2 pores, or inaperturate. Ovary inferior [or rarely secondarily superior], sometimes fused between flowers (Mitchella, Morinda, Mouretia), (1 or)2(-10)-celled (i.e., locular), with ovules 1 or 2 to numerous in each cell (i.e., locule) on basal, axile (i.e., inserted on septum), apical, or infrequently parietal (Ceriscoides, Gardenia) placentas, in staminate flowers usually with ovary reduced and pistillode composed of structures similar to but smaller than style and stigma, in distylous flowers usually with ovary similarly developed but style and stigma differing in size and position in flower and sometimes stigmas also differing in shape between long-styled and short-styled forms; style 1, terminal on ovary, developed or rarely reduced (Galium, Microphysa), variously glabrous to pubescent, surrounded at base by well-developed fleshy disk [or this rarely reduced], this disk variously annular, conical, 2-parted, or shallowly lobed, glabrous or rarely pubescent (Clarkella, Mouretia, Timonius); stigmas free or rarely fused to anther connectives (Acranthera), 1- or 2(-10)-lobed (i.e., these lobes often equivalent to "stigmas 1 or 2 to 10" of some authors), with whole stigma or lobes variously capitate, linear, spatulate, clavate, lobed, or infrequently mitriform (i.e., shaped like a drinking glass) to cylindrical with recessed attachment (Canthium, Mitragyna, Pyrostria), glabrous or infrequently pubescent (Clarkella, Hyptianthera), variously included to exserted, with receptive surfaces introrse, apical, or internal. Infructescences generally similar to inflorescences but occasionally with part or all changing color, orientation, shape, and/or other characteristics as the fruit mature. Fruit simple or rarely multiple (i.e., a syncarp; Mitchella, Morinda, Nauclea), variously capsular with dehiscence loculicidal, septicidal, circumscissile (i.e., around equator or middle; Mitracarpus), or through an apical beak (i.e., prolonged disk portion, sometimes to give appearance of partially superior ovary; Hedyotis, Neanotis, Neohymenopogon, Ophiorrhiza, Pentas, Spiradiclis) or operculum (i.e., circular lid; Argostemma, Leptodermis, Leptomischus, Mouretia, Pseudopyxis); or fleshy, small to quite large, and baccate (i.e., with numerous seeds enclosed by fleshy to juicy pulp or endocarp and usually indehiscent); or drupaceous (i.e., with 1 to several seeds enclosed in pyrenes), fleshy to occasionally dry, and indehiscent or infrequently dehiscent releasing pyrenes (Paederia, Serissa); or schizocarpous (i.e., dry and separating into segments) with mericarps (i.e., segments, cocci, nutlets) indehiscent (e.g., Asperula, Cephalanthus, Richardia); calyx limb persistent or deciduous usually leaving a circular scar, sometimes with persistent carpophore or septum (Adina); pyrenes (i.e., seeds enclosed in and dispersing with endocarp layer) when present and ovules all developed 1-10-locular and 1-10-seeded (i.e., fruit containing several pyrenes and each pyrene with 1 seed in 1 locule, or pyrenes solitary in each fruit and comprising entire ovary), ellipsoid to subglobose, plano-convex (i.e., hemispherical), concavo-convex, lenticular, or angled (i.e., narrow with 2 large inner faces and a small outer face), with outer wall hard to cartilaginous (Caelospermum) or infrequently papery (Coffea, Pavetta), smooth to ridged or sulcate on dorsal (i.e., abaxial) surface, without (Psychotria) or usually with evident preformed germination slits, pores, and/or opercula generally on ventral (i.e., adaxial) surface, rarely winged (Paederia) or pubescent (Caelospermum, Paederia); seeds 1 to numerous, small (0.1-1.9 mm), medium-sized (2-5 mm) to large (5.1-20 mm), variously ellipsoid, lenticular, flattened, oblanceoloid, angled, or plano-convex, smooth to variously winged, foveolate, tuberculate, papillose, and/or striate; endosperm (i.e., albumen) fleshy, oily, corneous (i.e., horny) and entire or infrequently ruminate (Psychotria), or rarely absent (Antirhea); embryo variously shaped. x = 6-17, most commonly 11, less frequently 9 or 12.
About 660 genera and 11,150 species: cosmopolitan family, with most genera and species in humid tropical regions; 97 genera (three endemic, ten introduced) and 701 species (352 endemic, 23 introduced, six of unconfirmed occurrence) in China.