Linaria markotchensis Popovich & Zernov, 2022

Popovich, Anton V. & Zernov, Alexander S., 2022, Linaria markotchensis (Plantaginaceae), а new species from the Western Caucasus, Phytotaxa 547 (1), pp. 105-113 : 108-110

Linaria markotchensis Popovich & Zernov , spec. nov. ( Figs 1–3 )

Diagnosis:—The new species differs from Linaria altaica Fisch. ex Ledeb. , L. macroura and L. odora (M.Bieb.) Fisch. by the surface of the seed disk which is covered with tubercles and short ridges (versus the smooth surface of the seed disk). It differs from L. biebersteinii and L. vulgaris by its low stems (3.5–)4.5–10(–15) cm long (versus 30–90 cm long); linear, semicylindrical, fleshy (succulent) and very narrow leaves (versus lanceolate or linear-lanceolate, nonsucculent and broader leaves); and inflorescence axis and pedicels glabrous (versus covered with simple or glandular trichomes).

Type: — RUSSIA. Krasnodar Territory: Gelendzhik, southern side of Markotkh Ridge , «Leont’ev Bugor» between Trubetskaya and Penaiskaya gorges, 100 m a.s.l., scree slope of the north-eastern exposition, petrophytic vegetation, 44°40’47.4” N, 37°53’58.1” E, 4 Juny 2019, A. Popovich (holotype MW barcode MW0595722 ) .

Description: —Herbaceous perennial plants. Rhizome long, thin, forming suckers ( Fig. 1A ). Stems usually simple, less often branching at the base or sometimes in the upper part, (3.5–)4.5–10(–15) cm long, almost always erect, glabrous, glaucous ( Fig. 1A–B ; 2A–C ). Leaves always alternate. Basal leaves scales, shorter than internodes, adjacent to the stem, 1.5–2.0(–4.5) mm long. Cauline leaves numerous (30–60), (9–)13–20(–24) × 0.8–1.1 mm, linear, semicylindrical, fleshy (succulent), straight or saber-curved, apical ones obtuse, grooved (sometimes obscurely) on the adaxial side. Bracts flattened, fleshy, 0.2–0.4 mm wide. Inflorescence open oliganthous bracteous raceme, 1.0–4.0 cm long, terminal or sometimes also lateral; axis glabrous ( Fig. 1B–C ). Flowers (2)4 to 6(10). Pedicels glabrous, always straight, (1.2–)2.0–3.0(–8.0) mm long. Calyx lobes greenish, lanceolate, oblong-lanceolate or ovoid-lanceolate, obtuse, cartilaginous and with scattered, very small glandular trichomes along the margin; equal in length or two lower lobes are slightly longer and narrower than three upper ones, 2.0–2.5(–3.0) mm long, 1.0– 1.2 mm wide. Corolla yellow, (6.2–)7.0–8.2(–10.0) mm (without spur); tube 1.8–2.4(–3.0) mm wide; corolla tube and the base of the upper and lower lips outside with scattered, very small glandular trichomes. Spurs (6.0–)7.0– 9.5 mm long, always glabrous, narrowly conical, straight or slightly curved, often due to insect damage; rarely the spurs are almost aborted due to abnormal flower development ( Fig. 1D–F ). Upper lip bilobate, up to 5–7 mm long, about 4 mm wide; lower lip trilobate, about 4–6 mm long, middle lobe 1.5–2.5 mm long, shorter than the lateral ones, with a brighter yellow spot, hairs yellowish or partly whitish. Two short stamens 4 mm long, as long as the column, slightly thickened and with single papillae in the lower part. Two long stamens about 6 mm long, thickened with numerous papillae at the base ( Fig. 1G ). Column 3–5 mm long, with rare minute glandular trichomes in the middle and lower parts. Ovary glabrous or with single minute glandular trichomes. Fruits two-nest capsules; ellipsoidal, larger (3.0–6.0 mm long) in the lower and middle parts of the raceme, ellipsoidal or globular, smaller (2.0–4.0 mm long) in the upper part of the raceme ( Fig. 3C ); nests equal, opened with 3 denticles at the top, denticles reaching 1/3 of the capsule ( Fig. 3A–B ). Capsules 4.5 mm long in average, with (4–)8–14(–19) seeds in larger capsules and 2–8(10) seeds in smaller capsules. Seeds (2.0–)2.3–2.6(–2.8) × (1.5–)1.8–2.0(–2.3) mm, discoid, reniform to orbicular-reniform, concave-convex or flat-convex ( Fig. 3D ); wing (0.3–)0.4–0.6(–0.8) mm broad, black, usually noticeable notched in the area of the funiculus; disk reniform, black shiny, with tuberculate and short ridges ( Fig. 3E ).

Etymology:—The species is named after the Markotkh Ridge, the only territory where it is distributed. Distribution:— Russia, Krasnodar Territory, Gelendzhik; Western Caucasus, southern side of the Markotkh Ridge ( Fig. 4 ). The new species is known from several localities which are no more than 1.5 km apart. The area of the species distribution is about 1.2 km 2.

Habitat and phenology:—Rocky-scree slopes, marl screes, as part of a sparse petrophytic hemixerophytic vegetation, at altitudes of 100– 130 m. Flowering starts in the second half of May and continues till the end of July, second flowering in September–October. Fruiting occurs in July–August, second fruiting in October–November.

Specimens examined(paratypes):— RUSSIA. Krasnodar Territory: Gelendzhik,southern side of Markotkh Ridge : «Leont’ev Bugor» between Trubetskaya and Penaiskaya gorges, 100 m a.s.l., scree slope of the north-eastern exposition, petrophytic vegetation, 44°40’47.3” N, 37°53’58.5” E, 4 Juny 2019, №4, Popovich ( MW barcode MW0595727 ); ib., 44°40’47.4” N, 37°53’58.6” E, 4 Juny 2019, №5, Popovich ( MW barcode MW0595728 ); ib., 44°40’47.9” N, 37°53’58.5” E, 4 Juny 2019, №6, Popovich ( MW barcode MW0595726 ); ib., 44°40’47.9” N, 37°53’58.3” E, 4 Juny 2019, №7, Popovich ( MW barcode MW0595724 ); ib., 44°40’47.9” N, 37°53’58.4” E, 4 Juny 2019, №8, Popovich ( MW barcode MW0595725 ); ib., 44°40’47.5” N, 37°53’58.9” E, 4 Juny 2019, №9-10, Popovich ( MW barcode MW0595723 ); ib., 44°40’47.1” N, 37°53’59.1” E, 10 September 2017, Popovich ( MW barcode MW1005060 ); ib., 44°40’47.1” N, 37°53’58.5” E, 10 September 2017, Popovich ( MW barcode MW1005061 ); ib., 44°40’47.7” N, 37°53’58.1” E, 28 May 2018, Popovich ( MW barcode MW0595730 ); near the memorial «Battery of captain Zubkov», 130 m a.s.l., scree slope of the north-eastern exposition, petrophytic vegetation, 44°41’25.7” N, 37°52’42.0” E, 13 Juny 2019, Popovich ( MW barcode MW0595731 ); Penaiskaya gorge, scree slope of the south-eastern exposition, in petrophyton, 44°41’16.6’’ N, 37°53’11.7’’ E, 18 July 2019, Popovich ( MW barcode MW0595729 ) .

Figures

FIGURE 1. Linaria markotchensis in its type locality in Krasnodar Territory. A. Habit of excavated plant. B. Flowering plant. C. Upper part of the inflorescence. D. Flowers, lateral view and view from the top. E. Inflorescence.F. Flower with an anomalous spur.G. Thickened bases of long stamens with numerous papillae. Photos by A.V. Popovich (A. 15 November 2017; B–G. 04 June 2019).

FIGURE 2. Linaria markotchensis in its type locality in Krasnodar Territory (Gelendzhik, southern side of Markotkh Ridge, «Leont’ev Bugor» between Trubetskaya and Penaiskaya gorges). A–C. Flowering plants. Photos by A.V. Popovich (A, C. 04 June 2019; B. 24 July 2018).

FIGURE 3. Linaria markotchensis in its type locality in Krasnodar Territory.A. Generative plant in the period of seed dissemination. B. Opened capsules. C. Upper part of the inflorescence with ripening fruits. D. Scanning electron micrographs of a seed (bar = 300 μm). E. Scanning electron micrographs of the surface disk of a seed (bar = 100 μm). Photos by A.V. Popovich (A, C. 15 November 2017; B. 24 July 2018) and S.G. Zaychenko (D, E).

FIGURE 4. Distribution map of Linaria markotchensis in the Western Caucasus.