Linaria tenuis (Viv.) Sprengel, Syst. Veg. ed. 16 2: 795 (1825).
Annual, glabrous or sometimes sparsely glandular-pubescent in inflorescence and on sterile stems; fertile stems 1-3, 6-30 (-58) cm, erect, simple or branched; sterile stems 1-5, prostrate to decumbent. Leaves of fertile stems 8-60 x 0.5-1.8 mm, filiform or linear, obtuse to subacute, flat or revolute, mostly alternate, often restricted to lower half of stems; leaves of sterile stems 4-11 x 0.5-1.5 mm, linear-elliptic, obtuse, flat, fteshy, opposite or 3- or 4-verticillate. Inflorescence with 3-14 flowers, dense to lax in flower and fruit. Bracts 2-10 mm, linear to lanceolate, obtuse, scarious. Pedicels erect or erecto-patent, often adnate for up to 0.5 length to stem; 1.5-3.5 mm in flower, 2.5-5 mm in fruit. Calyx-lobes subequal, scarcely accrescent, 2.5-6 x 0.5-1.7 mm, linear-lanceolate, subacute, green, the margin scarious, white. Corolla 12-17 mm, yellow; adaxial lip sinus 1-1.5 mm; abaxial lip sinus 0.6-1 mm; spur 3.5-6 mm, straight, much shorter than rest of corolla. Style bifid. Capsule 3.5-6 x 3-4.5 mm, oblong-ovoid, glabrous; loculi subequal, each loculus dehiscing by 3 (-5) teeth. Seeds 0.7-0.8 mm, reniform to irregularly tetrahedral, strongly transversely ridged, dark grey; transverse ridges 5-9, discrete or rarely anastomosed; periclinal wall of testa-cells verruculate, the margin not or scarcely raised except for angular marginal papilla towards ridge-apex, the median papilla usually present, conical or narrowly conical, acute, usually longer than broad. Modified from Sutton (1988).
NC & NE Africa, SW Asia. Ij Iq Li Ls Sn? Sr Tn.
Type: LIBYA: In tumulis arenosis Magnae Syrteos Viviani s.n. (FI) [Murbeck (1898) has proposed a neotype: TUNISIA: Sfax, 2 vi 1834 Kralik 118 (LD, duplicate at K! seen by Murbeck) cf. Viano, 1978a: 63].