1	"Prostrate to weakly ascending herbs of shallow water or wet mud; flowers tiny, unisexual, without calyx or corolla, the males comprising a single stamen, the females comprising 2 fused carpels"	Callitriche
1	"Erect to prostrate herbs of dryland to wetland habitats; flowers bisexual, with calyx and corolla and 2-4 stamens"	2
2	"Leaves all in a basal rosette; flowers in heads or spikes on a distinct scape, rarely solitary; corolla membranous to scarious; stamens long-exsert"	Plantago
2	"Leaves cauline (sometimes reduced to scales); flowers various, not usually in heads or spikes; corolla petaline; stamens included"	3
3	"Bracteoles present"	4
3	"Bracteoles absent"	11
4	"Sepals fused for more than half their length (in Centranthera the tube deeply split on abaxial side)"	Limnophila
4	"Sepals free for more than half their length"	5
5	"Fertile stamens 4"	6
5	"Fertile stamens 2"	10
6	"Calyx with upper sepal larger than other 4. Anthers of lower (longer) pair of stamens 1-celled, of the upper pair 2-celled"	Adenosma
6	"Calyx with 5 equal sepals or more than 1 larger. Anthers 2-celled"	7
7	"Sepals unequal, outer 3 very broad"	8
7	"Sepals equal. Anther cells separate"	9
8	"Bracteoles at very base of pedicel. Corolla yellow. Anther cells separate. Capsule septicidal. Plant drying deep brown"	"Mecardonia {Mecardonia procumbens}"
8	"Bracteoles just below calyx. Corolla with lobes white or pale blue, sometimes yellow-centred. Anther cells contiguous. Capsule loculicidal or also septicidal"	Bacopa
9	"Capsules septicidal (the septum remaining attached to valves)"	Stemodia
9	"Capsules septifragal (the septum remaining attached to central placental column)"	Limnophila
10	"Sepals 5, unfused. Corolla tubular, the lobes 5, much shorter than tube. Stigmas 2, flaplike. Leaves palmately veined"	Gratiola
10	"Sepals 4 to 5 (to 6), partly fused. Corolla irregularly rotate, lobes 4 to 5 (to 6) much longer to hardly shorter than tube. Stigma simple, capitate. Leaves pinnately veined"	Veronica
11	"Sepals fused for more than half their length"	Limnophila
11	"Sepals free for more than half their length"	12
12	"Corolla closed at mouth by palate (bumps) on lower side: base of tube spurred or swollen on lower side. Leaves alternate, at least in upper parts, rarely (in Misopates {Misopates orontium}) opposite throughout"	13
12	"Corolla mouth open, with or without palate; base of tube straight"	16
13	"Corolla tube swollen at base. Capsule asymmetrical, with base of adaxial (lower) cell wholly in front of pedicel"	"Misopates {Misopates orontium}"
13	"Corolla tube spurred at base. Capsule symmetrical at base"	14
14	"Leaf blades reniform to semi-circular, lined by 5 to 9 rounded to triangular lobes, palmately veined. Plant trailing. Capsule dehiscing by irregular longitudinal apical slits"	"Cymbalaria {Cymbalaria muralis subsp. muralis}"
14	"Leaf blades entire or with a pair of large basal lobes, pinnately veined. Plant erect or procumbent"	15
15	"Capsule dehiscing by irregular longitudinal slits. Leaves sessile. Plant erect. Flowers in terminal racemes or spikes"	Linaria
15	"Capsule dehiscing by pores opening by detachable lid. Leaves petiolate. Plant procumbent to ascending. Flowers solitary"	Kickxia
16	"Leaves opposite or whorled"	17
16	"Leaves alternate, at least in upper parts"	21
17	"Fertile stamens 2, sometimes with 2 staminodes"	"Dopatrium {Dopatrium junceum}"
17	"Fertile stamens 4"	18
18	"Sepals 4 (to 5 in other spp.). Corolla rotate, 4-lobed"	"Scoparia {Scoparia dulcis}"
18	"Sepals 5. Corolla bilabiate or more or less rotate, 5-lobed"	19
19	"Corolla with tube more or less obsolete, bilabiate, the lower lip deeply concave, appendaged in throat and much larger than upper lip"	"Angelonia {Angelonia salicariifolia}"
19	"Corolla with definite tube, bilabiate or more or less rotate"	20
20	"Corolla distinctly bilabiate, with upper lobes recurved. Anther cells separated. Capsule septifragal (septum remaining attached to central placental column)"	Limnophila
20	"Corolla more or less rotate or bilabiate, with upper lip porrect (stretched forward). Anther cells confluent. Capsule septicidal or loculicidal"	"Ourisia {Ourisia integrifolia}"
21	"Corolla with tube more or less obsolete, bilabiate, the lower lip deeply concave, appendaged in throat and much longer than upper lip"	"Angelonia {Angelonia salicariifolia}"
21	"Corolla bilabiate or more or less regular, with definite tube"	"Digitalis {Digitalis purpurea}"