Linaria caesia (Pers.) F.G. Dietr., Nachtr. Vollst. Lexic. 4: 411 (1818).
Somewhat glaucous perennial, occasionally annual or biennial, glabrous except for the sparsely glandular-pubescent infIorescence; fertile stems usually numerous, 10-30 (-50) cm, ascending to suberect, usually simple; sterile stems usually numerous, prostrate to ascending. Leaves of fertile stems 3-15 (-25) x 0.5-1.2 mm, linear-subulate to narrowly oblong, acute, fIat, attenuate, the lowermost verticillate in whorls of 4, the upper alternate; leaves of sterile stems similar to those of the fertile stems but more crowded, verticillate in whorls of 4. InfIorescence with (2-) 5-15 fIowers, dense in fIower, lax in fruit. Bracts 2-7 mm, linear, acute. Pedicels 1-2 (-5) mm in fIower and fruit, erecto-patent. Calyx-lobes unequal, oblong to linear-spathulate, acute or subacute; adaxial lobe 4-5 x 0.8-1.2 mm in fIower, 6-8 x 0.9-1.3 mm in fruit; abaxial lobes 2.5-3.5 x 1-1.3 mm in fIower, 4-5 x 1-1.5 mm in fruit. Corolla 19-25 mm, yellow with reddish-brown veins; tube 4-5 mm broad; adaxial lip sinus 3-5 mm; abaxial lip sinus 1.5-3.5 mm; spur 10-12.5 mm, 1.3-2 mm broad at base, somewhat curved, equalling or scarcely exceeding rest of corolla. Capsule 4-6 mm, globose, glabrous. Seeds 2-2.5 mm, orbicular or reniform-orbicular, plano-convex or somewhat concavo-convex, black and metallíc-shiny; hilum narrow; wing 0.4-0.7 mm broad, thin, smooth, not papillate, black or dark grey; disc somewhat reinform, without tubercles or papillae; periclinal wall of testa-cells tabular, smooth or verrucate, the anticlinal walls of testa-cells straight with ridge over junction. Modified from Sutton (1988).
2n = 12 (Valdés, 1970b: 245).
C Spain. Hs.
Type: SPAIN: Madrid; Cerro Negro, 1806 Lagasca s.n. (lecto. (Valdés, 1970: 131, 133) G-DC).