Linaria purpurea (L.) Miller, Gard. Dict. ed. 8: no. 5 (1768).
Glabrous, green or somewhat glaucescent perennial often with stout, woody rootstock, not stoloniferous; fertile stems usually numerous, (20-) 40-90 (-140) cm, erect or ascending, usually robust, up to 8 mm thick, simple or branched above, more or less densely leafy below, less densely leafy above, sometimes tinged with purple below; sterile stems 0-20, decumbent to ascending. Leaves of fertile stems 20-60 x 1-4 (-8) mm, linear or linear-oblanceolate, acute or subacute, flat or somewhat revolute, attenuate, alternate above, 4- to 6-verticillate below; leaves of sterile stems similar to those of fertile stems, verticillate in whorls of 4-6. Inflorescence with numerous flowers, usually dense in flower and fruit. Bracts 1.5-5.5 mm, linear, acute, usually equalling or exceeding pedicels in fruit. Pedicels 1.5-3 mm in flower, 2-3.5 (-4.5) mm in fruit, erect. Calyx-lobes equal, 1.2-3.5 x 0.5-1.2 mm, linear-lanceolate or lanceolate-ovate, acute to subobtuse, the margins white-scarious towards base. Corolla 9-12 (-17) mm, purplish-violet or lilac with violet veins, rarely pink, the palate sometimes lilac or whitish-yellow; tube 1.5-2.5 mm broad; adaxial lip sinus 1-1.3 mm; abaxial lip sinus (0.6-) 0.8-2 mm; spur 5-6.5 (-9) mm, 1-2 mm broad at base, linear, curved, acute, more or less equalling rest of corolla. Capsule 2.5-4 mm, cordate to depressed-globose, emarginate, glabrous. Seeds 0.8-1.2 mm, crescenti-trigonous or sometimes tetrahedral, blackish-brown; longitudinal marginal ridges 0.1-0.15 mm, rounded or subacute, the intervening faces with short, anastomosed ridges or occasional discrete tubercles; periclinal wall of testa-cells tabular, rugulate, that of cells of ridge-bases and interstices papillate, the papillae large, conical or rounded. Modified from Sutton (1988).
2n = 12 (Heitz, 1926; Valdés, 1970b; Fernandes, Queirós and Santos, 1977: 49).
C & S Italy, cultivated and naturalized in temperate regions. It Si [Br Cn Cz Hb Nz Us]. Type: ITALY: "9 purpureum" (ad radices Vesuvii) sine leg. (syn. (cf. Viano, 1878b: 255) LINN-767.13!).