Linaria (Peskova, 2004)

Popovich, Anton V. & Zernov, Alexander S., 2022, Linaria markotchensis (Plantaginaceae), а new species from the Western Caucasus, Phytotaxa 547 (1), pp. 105-113 : 112

Key to the species of Linaria in the Western Caucasus

1. Corolla violet to reddish-purple........................................................................................................................................ L. incarnata

– Corolla yellow ....................................................................................................................................................................................2

2. Seeds angled, non-discoid. Leaves always alternate, linear-lanceolate to broadly ovate ..................................................................3

– Seeds discoid, with a marginal wing. Leaves alternate; if verticillate then plants annual .................................................................4

3. Stems procumbent to ascending, 15-25(–30) cm. Leaves ovate, 6–14 × 3–7 mm ............................................................ L. sabulosa

– Stems erect, 30–130 cm. Leaves linear-lanceolate to broadly ovate, 15–70 × 5–25 mm ............................................. L. genistifolia

4. Plants annual. Leaves verticillate on sterile stems and fertile stems below. Corolla (with spur) 5–9 mm .......................... L. simplex

– Plants perennial. Leaves always alternate. Corolla larger ..................................................................................................................5

5. Disc of seeds smooth. Corolla (with spur) 28–38 mm. Sepals broadly ovate to elliptical............................................... L. macroura

– Disc of seeds tuberculate. Corolla smaller .........................................................................................................................................6

6. Small plants with erect or ascending stems, (3.5–)4.5–10(–15) cm. Leaves longer (9–24 mm) and wider (0.8–11 mm), linear, succulent. Corollas (with spur) 12.2–19.5 mm. Spur equal to corolla. Inflorescence axis and pedicels glabrous .............................. .................................................................................................................................................................................. L. markotchensis

– Large plants with erect stems, 30–110 cm. Leaves longer (20–60 mm) and wider (2–7 mm), linear-lanceolate to linear-oblanceolate, non-succulent. Corollas (with spur) 21–33 mm. Spur shorter than corolla. Inflorescence axis and pedicels pubescent...................7

7. Corolla 21–28 mm. Stems often hairy in lower half. Inflorescence axis and pedicels with long simple trichomes............................ ..................................................................................................................................................................................... L. biebersteinii

– Corolla (19–) 25–33 mm; stems glabrous in lower half. Inflorescence axis and pedicels with glandular trichomes........................... ............................................................................................................................................................................................ L. vulgaris