1	"Plant generally aquatic, or plants in wet soil or mud"	2
1	"Plant generally terrestrial, generally of drier habitats"	6
2	"Corolla and calyx clearly present; plants in wet soil or mud"	3
2	"Corolla 0; calyx generally 0, except occasionally present as minute rim on ovary; plants aquatic"	5
3	"Stamens 4, staminode 0"	Bacopa
3	"Stamens 2, staminodes 2 (forming corolla throat ridges and with free, forked, filament-like tips in <i>Lindernia</i>)"	4
4	"Distal leaves scale-like; corolla 4--7 mm"	Dopatrium
4	"Distal leaves lanceolate to ovate; corolla 7--10 mm"	Lindernia
5	"Leaves generally opposite; ovary superior, styles 2"	Callitriche
5	"Leaves in whorls of 6--12; ovary inferior, style 1"	"Hippuris {Hippuris vulgaris}"
6	"Corolla dry, scarious, translucent, persistent in fruit; leaves generally basal, veins generally +- parallel; fruit circumscissile"	Plantago
6	"Corolla of petal-like texture, variously colored, but not scarious or translucent, generally not persistent in fruit; leaves basal or basal and cauline, veins generally pinnate or palmate; fruit generally not circumscissile"	7
7	"Leaves generally alternate (except proximal generally opposite in <i>Antirrhinum</i>, <i>Cymbalaria</i>, <i>Mohavea</i>, <i>Pseudorontium</i>; proximal-most opposite on seedlings in <i>Maurandella</i>), not all basal"	8
7	"Leaves generally opposite, sometimes whorled or all basal"	18
8	"Corolla base neither spurred nor sac-like, throat open, floor without longitudinal folds, or throat +- closed; fruit generally loculicidal or opening by irregular bursting near tip"	9
8	"Corolla base spurred or sac-like (except <i>Holmgrenanthe</i>, corolla throat open, floor with 2 longitudinal folds); fruit generally dehiscent by terminal slits or pores (circumscissile)"	10
9	"Corolla 40--60 mm, lower lip not swollen, throat open; fruit generally loculicidal"	"Digitalis {Digitalis purpurea}"
9	"Corolla 8--9 mm, lower lip swollen, +- closing throat; fruit opening by irregular bursting near tip"	"Pseudorontium {Pseudorontium cyathiferum}"
10	"Leaves palmately veined, entire to lobed; petioles 5--33 mm"	11
10	"Leaves not palmately veined, generally entire, generally +- sessile (or petioles <= 30 mm)"	13
11	"Corolla base spurred"	"Cymbalaria {Cymbalaria muralis}"
11	"Corolla base not spurred"	12
12	"Leaves +- round to reniform; neither stems or petioles twining; corolla white to pale yellow; pedicels 1--4 mm"	"Holmgrenanthe {Holmgrenanthe petrophila}"
12	"Leaves hastate to sagitate; corolla pink, red, to violet distally; stems or petioles twining; pedicels 12--47 mm"	"Maurandella {Maurandella antirrhiniflora}"
13	"Stem twining or decumbent"	14
13	"Stem erect"	15
14	"Plant glabrous (except stem base, inflorescence); pedicels twining or U-shaped, or bractlets subtended by twining branchlets, these reduced at distal nodes; leaves linear to ovate"	Antirrhinum
14	"Plant hairy; pedicels straight; branchlets subtending bracts 0; leaves ovate to hastate or sagittate --- fruit circumscissile"	Kickxia
15	"Corolla base spurred; plant generally glabrous"	16
15	"Corolla base sac-like; plant generally hairy (at least inflorescence), rarely glabrous throughout"	17
16	"Flowers yellow, red-violet, purple, or occasionally 2-colored; corolla lower lip >= upper lip"	Linaria
16	"Flowers blue to violet; corolla lower lip >> upper lip"	"Nuttallanthus {Nuttallanthus texanus}"
17	"Stamens 4, anther sacs 2 per stamen; fruit asymmetric, dehiscing by 1--2 pores near tip"	Antirrhinum
17	"Stamens 2, anther sacs 1 per stamen; fruit symmetric, dehiscent by irregular slit at tip"	Mohavea
18	"Stamens 2, staminodes 0 or 2"	19
18	"Stamens 4, staminode 0 or 1"	23
19	"Leaves basal, long-petioled; inflorescence scapose"	Synthyris
19	"Leaves cauline, sessile to short-petioled; inflorescence not scapose"	20
20	"Corolla +- radial, generally 4-lobed, tube << lobes; sepals generally 4(5)"	Veronica
20	"Corolla 2-lipped, 5-lobed, tube > lobes; sepals generally 5"	21
21	"Anther sacs of each stamen separated, parallel; corolla tube 4-angled"	Gratiola
21	"Anther sacs of each stamen touching, not parallel; corolla tube cylindric"	22
22	"Distal leaves scale-like; corolla 4--7 mm"	"Dopatrium {Dopatrium junceum}"
22	"Distal leaves lanceolate to ovate; corolla 7--10 mm"	"Lindernia {Lindernia dubia}"
23	"Calyx tube well developed"	24
23	"Calyx segments +- free"	25
24	"Stamens included in keeled lower central corolla lobe"	Collinsia
24	"Stamens exserted, lower central corolla lobe not keeled"	"Tonella {Tonella tenella}"
25	"Corolla spurred at base of tube"	26
25	"Corolla not spurred, occasionally sac-like at base"	28
26	"Stem decumbent; flower 1 in axils"	Kickxia
26	"Stem erect; inflorescence a terminal raceme"	27
27	"Flowers yellow, red-violet, purple, or occasionally 2-colored; corolla throat swelling obvious, not white-ridged"	Linaria
27	"Flowers blue; corolla throat swelling +- obscure, white-ridged"	"Nuttallanthus {Nuttallanthus texanus}"
28	"Staminode 0"	29
28	"Staminode 1"	31
29	"Leaves in whorls of 3; flowers > 2 cm, bright red"	"Gambelia {Gambelia speciosa}"
29	"Leaves opposite; flowers < 2 cm, not red"	30
30	"Leaves generally narrowly +- ovate to +- round, +- entire; corolla generally white to pink"	Bacopa
30	"Leaves +- lanceolate, toothed; corolla violet to purple"	"Stemodia {Stemodia durantifolia}"
31	"Fertile filament bases glabrous, attached to corolla at different levels"	Penstemon
31	"Fertile filament bases densely hairy, attached to corolla at 1 level"	32
32	"Subshrub or shrub; anthers glabrous; seeds angled"	Keckiella
32	"Perennial herb; anthers woolly; seeds winged"	"Nothochelone {Nothochelone nemorosa}"