Linaria miller Gard. Dict. abridged ed. 4 2 (1754).
Annual, biennial or perennial herbs; stems heteromorphic or more or less homomorphic, the epicotylary stems usually few and degenerate, the hypocotylary secondary stems often abundant and dominant, the branches not cirrhous. Leaves homomorphic or somewhat heteromorphic, simple, entire, pinnately veined or with several subparallel major veins from base, sessile, usually verticillate below, alternate above. Flowers zygomorphic, pedicellate or sessile, in terminal bracteate racemes, spikes, panicles or rarely flowers solitary in leaf-axils. Bracts usually smaller than foliage leaves, sometimes leaf-like, very rarely subtending additional axillary shoots. Pedicels not cirrhous, sometimes becoming recurved or deflexed. Calyx deeply divided, the lobes entire, valvate, equal or unequal, the adaxial lobe longest or very rarely shortest, shorter than or rarely longer than corolla-tube. Corolla with tube more or less cylindrical, calcarate abaxially at base; limb bilabiate, the lips equal or somewhat unequal, the adaxial lip erecto-patent to patent, shorter than or sometimes longer than abaxial, the abaxial lip spreading to patent with prominent basal palate occluding or occasionally only partially occluding mouth of tube; spur narrowly conical, linear or filiform, often arcuate, usually conspicuous; lobes entire or very rarely emarginate. Fertile stamens 4, didynamous, included, the adjacent pairs of anthers marginally coherent, the connective not dilated above anthers; staminode minute. Style simple or bifid; stigma capitate, clavate, linear or sometimes with 2 (-3) discrete stigmatic areas, positioned between pairs of fertile stamens. Capsule oblong, ovoid or globose, the walls papery, the septum erect, straight; loculi many-seeded, equal or unequal, if unequal then adaxial exceeding abaxial, each loculus dehiscing by solitary pore opening by 3-5 teeth or valves from apex towards base. Seeds dorsi-ventrally or radially symmetrical or somewhat asymmetrical, ovoid, oblong, reniform, trigonous, tetrahedral or discoid, cristate, tuberculate, alveolate or smooth; hilum subbasal to submedian, often positioned in marginal ridge or wing of discoid seeds; ridges of angles or margins (1-) 2-6, thin and wing-like, inflated or interrupted and scarcely evident; periclinal wall of testa-cells tabular, tabular-convex or rarely concave, those of interstices and sides of ridges or tubercles often with median or marginal papilla, rarely bipapillate, smooth, verrucate, rugulate or reticulate; epicuticular waxes usually absent. Modified from Sutton (1988).
2n = 12, 24.
Europe except for extreme N, Asia except for SE and extreme N, N Africa, frequently introduced and naturalized elsewhere in temperate regions.
Type species: Linaria vulgaris Miller (Antirrhinum linaria L.).