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Plantaginaceae
See list of 18 genera in this family-
1a. Leaves 6–12 at each node, with entire blades; flowers with a single stamen borne at the summit of the ovary; calyx a minute rim around the apex of the ovary
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1b. Leaves 1 or 2 at each node (but crowded in the apical portion in Callitriche) or all basal, entire or toothed (in whorls of 3–6 in Veronicastrum, but then with serrate blades); flowers with 1–5 stamens, these not borne at the summit of the ovary; calyx absent or present and borne near the base of the ovary
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2a. Perianth absent; plants aquatic, with opposite leaves that are often crowded in the apical portion and forming a floating rosette [Fig. 766]
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2b. Perianth present; plants terrestrial (aquatic in Littorella); leaves not forming a floating rosette near the apex of the stem
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3a. Perianth inconspicuous, 3- or 4-merous, with an actinomorphic, scarious corolla [Figs. 771,774,775]; leaves all basal (opposite and borne on a stem in P. arenaria) [Fig. 771]
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4a. Scape 1- to 3-flowered [Fig. 771]; fruit an achene, 1-locular, 1-seeded; plants aquatic, with slender stolons
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4b. Scape many-flowered; fruit usually a pyxis, 2- or 3-locular, 2- to many-seeded; plants terrestrial or of tidal wetlands, without stolons
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3b. Perianth conspicuous and showy, with a zygomorphic, 5-merous corolla (appearing 4-merous in Veronica and Veronicastrum [Figs. 767,770,772]; leaves borne on a stem
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5a. Corolla with a slender, basal spur or a saccate swelling protruding between the 2 lower calyx lobes, and with a palate [Figs. 769,770]; foliage leaves usually alternate (sometimes the lower opposite, especially in Antirrhinum and Chaenorhinum)
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6a. Corolla with a saccate (i.e., pouch-like) swelling on the lower side; plants both with flowers arranged in a terminal raceme and with capsules dehiscing by terminal pores
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7a. Calyx lobes ± subequal, shorter than the basal, connate portion of the corolla; corolla 25–45 mm long; plants 40–80 (–120) cm tall, perennial
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7b. Calyx lobes unequal, all longer than the basal, connate portion of the corolla; corolla 10–15 mm long; plants (5–) 20–50 cm tall, annual
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6b. Corolla with a slender, basal spur [Figs. 769,770]; plants either with flowers in terminal racemes (but then with capsules opening by terminal slits) or with capsules dehiscing by apical pores (but then with solitary flowers in the axils of leaves)
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8a. Inflorescence a terminal raceme; capsules dehiscing by terminal slits; seeds with angular faces
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9a. Palate composed of 2 short, white ridges; seeds both ± smooth on the faces and wingless
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9b. Palate composed of a single, usually yellow or orange, ridge; seeds either with rugose or reticulate patterning or with wings or wing-like angles
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8b. Inflorescence a solitary flower in the axils of leaves; capsules dehiscing by 2 terminal pores (the pores eventually extending to the capsule base in Cymbalaria); seeds ellipsoid to ovoid
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10a. Stems upright; capsules pubescent, asymmetrical, one locule larger than the other
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10b. Stems prostrate; capsules glabrous, symmetrical, both locules of ± equal size
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11a. Leaf blades palmately veined, with 5–9 tooth-like lobes; stems rooting at the nodes in contact with the soil
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11b. Leaf blades pinnately veined, entire (rarely the lower minutely denticulate); stems not rooting at the nodes
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5b. Corolla lacking a slender, basal spur, without a palate except in Chelone and 1 species of Penstemon; foliage leaves opposite or whorled (alternate in Digitalis)
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12a. Foliage leaves alternate; inflorescence a secund raceme [Fig. 767]
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12b. Foliage leaves opposite or whorled; inflorescence various, but not a secund raceme
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13a. Androecium composed of 5 stamens—4 pollen-bearing stamens and 1 sterile stamen
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14a. Corolla subgaleate; sepals subtended by bractlets; sterile stamen shorter than the pollen-bearing stamens; seeds winged
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13b. Androecium composed of 2 or 4 stamens—all pollen bearing or 2 of the 4 composed of filaments only
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15a. Corolla apparently composed of 4 lobes due to fusion of the upper 2 petals [Fig. 778]; calyx composed of 4 sepals (5 sepals in Veronica officinalis); inflorescence a spike or raceme (the bracteal leaves ± similar to the foliage leaves in some Veronica, but then usually alternately arranged) [Figs. 776,777,778]
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16a. Leaves opposite, sometimes the upper alternate (rarely some whorled in V. longifolia and V. spuria); lobes of the corolla longer than the basal tube; capsules, before dehiscence, emarginate or lobed at the apex
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16b. Leaves mostly in whorls of 3–7; lobes of the corolla shorter than the basal tube; capsules, before dehiscence, tapering to the apex, not lobed
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15b. Corolla composed of 2 lips—the upper lip 2-lobed, the lower lip 3-lobed [Fig. 768]; calyx composed of 5 sepals; inflorescence of solitary or whorled flowers in the axils of oppositely arranged foliage leaves [Fig. 768]
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17a. Sepals evidently connate in the basal portion; corolla 4–6 mm long, the middle lobe of the lower corolla lip declined below the lateral lobes and enfolding the 4 pollen-bearing stamens
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Each photo represents one genus in this family.