1. Stamens > in number than corolla lobes or > 15
2. Plant spiny or bristly
3. St very fleshy, generally spiny (in some Opuntia species only with glochids); leaves 0 or conic to cylindric, fleshy; petal-like parts many, overlapping in several series ..... CACTACEAE {G21}
3' St not or slightly fleshy, bristly with stinging hairs; leaves well developed, with expanded blade; petals 5, in 1 series ..... LOASACEAE (Eucnide)
2' Plant glabrous or ± hairy but not spiny or bristly
4. Petals or petal-like stamens many; leaves generally fleshy ..... AIZOACEAE {G14,15,21}
4' Petals 4 or 5, petal-like stamens 0; leaves generally thin
5. Herbage glabrous to soft-hairy, sometimes glandular ..... ERICACEAE {G18,19,24}
5' Herbage stellate-hairy ..... STYRACACEAE {G19}
1' Stamens = in number to corolla lobes or fewer, generally <= 5
6. Ovary actually superior, surrounded by but not fused to hardened or winged base of corolla-like calyx that simulates an inferior ovary; style passing through constriction separating calyx base from petal-like portion and joining to top of ovary ..... NYCTAGINACEAE {G5,14,15,19}
6' Ovary truly inferior, fused to bases of surrounding flower parts; style not passing through a calyx constriction
7. Lvs alternate or all basal
8. Tendrils generally present; flowers unisexual — plant generally monoecious, leaves palmately veined, generally palmately lobed ..... CUCURBITACEAE {G6,8,14,21}
8' Tendrils 0; flowers bisexual or unisexual
9. Infl a head subtended or ± enclosed by involucre; calyx modified as pappus of bristles, scales, and/or awns, not green and leaf-like ..... ASTERACEAE (2) {G6,7,8,9,12,14}
9' Infl various but not a head; calyx of unmodified sepals, generally green
10. Stamens alternate corolla lobes; staminodes 0; flowers radial or bilateral; placentas axile or parietal ..... CAMPANULACEAE {G2,5,14}
10' Stamens opposite corolla lobes; staminodes alternate fertile stamens; flowers radial; placentas free-central ..... THEOPHRASTACEAE {G21}
7' Lvs opposite or whorled
11. Infl a peduncled pair of flowers — creeping subshrub, twining vine, or erect shrub
12. Fls sessile; fruits berries, sometimes fused ..... CAPRIFOLIACEAE (Lonicera)
12' Fls on slender pedicels; fruits capsules, not fused ..... LINNAEACEAE
11' Infl a head, spike, or cyme, or flowers solitary
13. Infl a head or dense, head-like spike, subtended or ± enclosed by ± calyx-like involucre
14. Anthers fused into tube around style ..... ASTERACEAE (2) {G6,7,8,9,12,14}
14' Anthers free
15. Lvs opposite ..... DIPSACACEAE
15' Lvs whorled ..... RUBIACEAE (Sherardia)
13' Infl various, not subtended or enclosed by ± calyx-like involucre
16. Herb or subshrub
17. Stamens 4 or 5; corolla radial, not spurred or with proximal bulge ..... RUBIACEAE (2) {G14}
17' Stamens 1 or 3; corolla often bilateral, often spurred or with proximal bulge ..... VALERIANACEAE {G14}
16' Shrub, tree, or woody vine
18. Infl a raceme or ± interrupted spike or flowers 1–2 in axils ..... CAPRIFOLIACEAE
18' Infl a head or compound cyme
19. Lvs compound ..... ADOXACEAE (Sambucus)
19' Lvs simple
20. Lvs 3–5-veined from base ..... ADOXACEAE (Viburnum)
20' Lvs 1-veined from base ..... RUBIACEAE (2) {G14}
