Leaves opposite or in whorls of 3 or 4, simple, margins mostly entire; stipules interpetiolar, free or fused, sometimes leaf-like and giving the appearance of whorled leaves.
Inflorescence a thyrse or dichasium, rarely flowers fused into a compound head or a single, terminal flower. Flowers usually actinomorphic, bisexual or unisexual and then plants monoecious or dioecious, mostly 4- or 5-merous. Calyx 3–6-lobed, often rudimentary or absent. Corolla mostly tubular and fused with the filaments at least at base, usually 3–5-lobed, sometimes ± 2-lipped. Stamens 4 or 5, alternate with petals; anthers 2-locular, dehiscing by longitudinal slits. Ovary inferior, 1- or more-locular; ovules 1–many per loculus; style undivided or bifid.
Fruit a capsule, drupe or schizocarp, individual fruit often fused into a compound fruit.
Key based on Morley & Toelken (1983); updated Louisa Murray Oct 2012 and K.L. Gibbons, Oct 2019.
| | Key to the genera | |
| 1 | Herbs mostly less than 1 m high, or if shrubby then with an inflorescence of globose compound heads | 2 |
| Woody plants, usually more than 1 m high | 16 |
| 2 | Leaves and stipules similar, giving the appearance of whorled leaves | 3 |
| Leaves and stipules dissimilar, latter much smaller
Back to 1 | 5 |
| 3 | Flowers in heads; calyx present, lobed | Sherardia |
| Flowers separate; calyx usually absent or present and then not lobed
Back to 2 | 4 |
| 4 | Corolla rotate, tube very short; fruit of 2 dry 1-seeded mericarps, falling separately at maturity | Galium |
| Corolla funnel-shaped with a distinct tube; fruit fleshy, 2-lobed, indehiscent
Back to 3 | Asperula |
| 5 | Flowers united into simple or compound heads by fusion of inferior ovaries | 6 |
| Flowers not united into heads by fusion of ovaries
Back to 2 | 7 |
| 6 | Flowers joined in 2- or 3-flowered heads, 5–11 heads on umbellate stalks | Pomax |
| Flowers joined in 2–7-flowered heads, several heads together in a compound globose head
Back to 5 | Opercularia |
| 7 | Inflorescences terminal, or if axillary then leafy bracts surrounding inflorescence | 8 |
| Inflorescences axillary; leafy bracts never present
Back to 5 | 13 |
| 8 | Flowers solitary | 9 |
| Flowers few to many in cymes or heads
Back to 7 | 10 |
| 9 | Calyx lobes absent; corolla short-campanulate | Nertera |
| Calyx lobes well-developed; corolla tubular to funnel-form or trumpet-shaped
Back to 8 | Leptostigma |
| 10 | Flowers in heads or clusters, surrounded by leafy bracts | 11 |
| Flowers in cymes, not surrounded by leafy bracts
Back to 8 | 12 |
| 11 | Plants erect; fruit of only 2, 1-seeded carpels, crowned by 2–4 persistent, erect calyx lobes | Spermacoce |
| Plants prostrate; fruit separating into 3 or 4 one-seeded mericarps, crowned by 4–6 eventually falling, radiating calyx lobes
Back to 10 | Richardia |
| 12 | Flowers bisexual; cymes regular; ovary 2-locular; fruit dry | Knoxia |
| Flowers unisexual and plants dioecious; cymes arranged in compound dichasia; ovary 1-locular; fruit fleshy
Back to 10 | Durringtonia |
| 13 | Non-succulent herbs of variable habit with stems to 40 cm long; stipules with long cilia | Diodia |
| Succulent prostrate herbs with stems to 20 cm long; stipules not as above
Back to 7 | 14 |
| 14 | Leaves less than 4 mm long; flowers sessile | Dentella |
| Leaves mostly more than 4 mm long; flowers pedicellate
Back to 13 | 15 |
| 15 | Corolla with a short or long tube, valvate, not persistent in fruit; pedicels to 20 mm long | Oldenlandia |
| Corolla rotate, persistent in fruit; pedicels to 6 mm long
Back to 14 | Synaptantha |
| 16 | Climbing plants | 17 |
| Shrubs or trees
Back to 1 | 19 |
| 17 | Fruits a drupe (fleshy) with 1-seeded pyrene | 18 |
| Fruits a schizocarp (drupe-like but dry)
Back to 16 | Paederia |
| 18 | Flowers fused, drupe with one seed | Gynochthodes |
| Flowers free, drupe with 4 seeds
Back to 17 | Coelospermum |
| 19 | Ovaries with 1–5 per ovules per loculus | 21 |
| Ovaries with at least 6 ovules per loculus
Back to 16 | 20 |
| 20 | Plant usually with spines, stipules interpetiolar, small, falling and leaving scars at nodes | Randia |
| Plant without spines, stipules interpetiolar, united into a sheath enclosing the terminal bud
Back to 19 | Atractocarpus |
| 21 | Stipules fused, at least at base | 22 |
| Stipules free
Back to 19 | 24 |
| 22 | Style exserted from corolla tube, the exserted part much longer than corolla lobes | Pavetta |
| Style slightly exserted from corolla tube, the exserted part shorter than or as long as corolla lobes
Back to 21 | 23 |
| 23 | Flowers in dense, axillary, 2–10 flowered subsessile clusters | Coffea |
| Flowers in terminal corymbs or panicles
Back to 22 | Ixora |
| 24 | Corolla lobes valvate in bud | 25 |
| Corolla lobes contorted and/or imbricate
Back to 21 | 29 |
| 25 | Flowers along leafy branchlets | 26 |
| Flowers along branches behind leaves or on axillary flower-bearing short shoots
Back to 24 | Coprosma |
| 26 | Flowers terminal or terminal and axillary in upper leaf axils, usually united into terminal inflorescences; ovules attached at base of ovary | Psychotria |
| Flowers axillary, in clusters or cymes, rarely solitary; ovules attached at or near top of ovary
Back to 25 | 27 |
| 27 | Stigma oblongoid, concave at base; style exceeding the corolla tube; inflorescences usually of branched pedunculate cymes | Psydrax |
| Stigma capitate or ovoid, convex at the base; style as long or slightly exceeding the corolla tube; inflorescences of sessile or short-peduncled umbelliform cymes
Back to 26 | 28 |
| 28 | Stigma ovoid, deeply 2-lobed; cymes pedunculate, 1–3-flowered; plants usually intricately and much branched; leaves nerveless or obscurely nerved | Everistia |
| Stigma capitate, obscurely 2-lobed, cymes sessile or pedunculate, 1–12-flowered; plants few-branched; leaves conspicuously nerved
Back to 27 | Cyclophyllum |
| 29 | Flowers unisexual in umbels on slender axillary peduncles | Hodgkinsonia |
| Flowers bisexual in clusters or dense cymes
Back to 24 | Triflorensia |
