1. Cleistogamous flowers formed at or below ground or water surface
2. Plant ± aquatic, submersed or emergent
3. Lvs opposite, palmately veined ..... PLANTAGINACEAE (Bacopa) (2)
3' Lvs alternate, parallel-veined ..... PONTEDERIACEAE (Heteranthera)
2' Plant terrestrial
4. Lvs petioled
5. Fr 3-angled achene, tightly enclosed by hardened perianth; cleistogamous flowers at stem base ..... POLYGONACEAE (Emex spinosa)
5' Fr ovoid to oblong capsule, not enclosed by hardened perianth; cleistogamous flowers in proximal leaf axils ..... VIOLACEAE (2) {G15,20,24}
4' Lvs sessile
6. Lvs 0.5–4 cm, ± linear, ± 1-veined, not sheathing; cleistogamous flowers at stem base ..... BORAGINACEAE (Pectocarya)
6' Lvs 2–9 cm, ovate to lance-elliptic, parallel-veined, sheathing; cleistogamous flowers underground ..... COMMELINACEAE (Commelina)
1' Cleistogamous flowers formed above ground or water surface
7. Lvs sheathing, linear, parallel-veined; spikelets of cleistogamous flowers enclosed within leaf sheaths or borne in panicle-like clusters ..... POACEAE {G2,6,8,13}
7' Lvs not sheathing, linear to ovate, not parallel-veined; spikelets of cleistogamous flowers 0
8. Lvs all basal, inflorescence or solitary flower scapose
9. Plant aquatic; leaves on rhizome or stolon, often bearing small, hollow bladders that suck in and trap small organisms when hairs at opening are triggered; flowers 1–few ..... LENTIBULARIACEAE (Utricularia subulata)
9' Plant terrestrial; leaves in basal rosette, not bearing traps; inflorescence a spike (flower 1) ..... PLANTAGINACEAE (Plantago) {G8,18,19}
8' Lvs all or mostly cauline
10. Ovary inferior
11. Infl a closed head enclosed by spine-tipped involucre bracts ..... ASTERACEAE (Centaurea melitensis)
11' Infl a spike or spike-like raceme or flowers sessile in leaf axils
12. Ovary/fruit not narrowed distally; sepals ascending or ± spreading ..... CAMPANULACEAE (Githopsis, Heterocodon, Triodanis)
12' Ovary/fruit distally narrowed; sepals not separating ..... ONAGRACEAE (Epilobium, Neoholmgrenia)
10' Ovary superior
13. Lvs ± fleshy
14. Plant 50–230 cm; leaves entire or toothed ..... BALSAMINACEAE ([Impatiens capensis]) (2)
14' Plant 1–30 cm; leaves entire ..... MONTIACEAE (Montia) {G2}
13' Lvs not fleshy
15. Lvs opposite
16. Lvs 2–7 mm, awl-shaped to oblong, bristle-tipped ..... CARYOPHYLLACEAE (Loeflingia)
16' Lvs linear, oblong, or lanceolate to ovate or round, not bristle-tipped
17. St square in ×-section; flowers in head-like axillary and terminal clusters — fruit 4 nutlets ..... LAMIACEAE (Lamium amplexicaule)
17' St round in ×-section; flowers axillary or in terminal raceme
18. Lvs of a pair unequal; ovule 1; fruit achene; perianth base hardened or 5-winged or -ribbed around fruit ..... NYCTAGINACEAE (Acleisanthes, Mirabilis albida)
18' Lvs of a pair equal; ovules several–many; fruit capsule; perianth base not hardened or 5-winged around fruit
19. Fr valves 3, ovary chambers 3 ..... CISTACEAE (Tuberaria)
19' Fr valves 2, ovary chambers 1–2
20. Sepals strongly fused ..... PHRYMACEAE (Mimulus)
20' Sepals ± free ..... PLANTAGINACEAE (Bacopa) (2)
15' Lvs alternate
21. Fr 1–4 hard, shiny gray nutlets ..... BORAGINACEAE (Lithospermum incisum)
21' Fr a capsule
22. Perennial
23. Lvs ± sessile; capsule flat ..... POLYGALACEAE (Polygala californica)
23' Lvs petioled; capsule ovoid to oblong ..... VIOLACEAE (2) {G15,20,24}
22' Annual
24. Infl or solitary flowers axillary; ovary chambers 5 ..... BALSAMINACEAE ([Impatiens capensis]) (2)
24' Infl terminal (axillary); ovary chambers 2–3
25. Infl a raceme ..... PLANTAGINACEAE (Antirrhinum, Dopatrium, Nuttallanthus)
25' Infl a head ..... POLEMONIACEAE (Collomia grandiflora)
