Orobanche dagestanica Ó. Sánchez, Piwow., Fateryga, Svirin & Murtaz., 2024

Piwowarczyk, Renata, Pedraja, Óscar Sánchez, Fateryga, Alexander V., Svirin, Sergey A. & Murtazaliev, Ramazan A., 2024, Orobanche dagestanica (Orobanchaceae): a new species from the Greater Caucasus, Phytotaxa 653 (1), pp. 67-78 : 68-71

Orobanche dagestanica Ó. Sánchez, Piwow., Fateryga, Svirin & Murtaz. , sp. nov. ( Figs. 1 , 2 )

Diagnosis:―Similar to other species in Orobanche subsect. Curvatae Piwowarczyk et al. (2017b: 133) but often conspicuously hairy in almost all aerial parts (white glandular hairs with ± pale yellowish glands) and usually rosaceous or more rarely carneous; inflorescence dense, frequently covering most of the stem; bracts shorter or ± equalling the corolla; calyx segments free, entire, shorter than corolla tube; corolla up to 30 mm, tubular-infundibuliform, ± strong narrowing at place of insertion of the filaments; filaments densely villous in the base to middle part and glandular-hairy above; stigma yellow. Documented to be parasitic only on Lophiolepis horrida (Adams) Bureš, Del Guacchio, Iamonico & P. Caputo and L. isophylla (Petr.) Bureš, Del Guacchio, Iamonico & P. Caputo. The habitat is alpine shale scree slopes of the Greater Caucasus.

Types:― RUSSIA. Dagestan: Dokuzparinskiy Distr., Mt. Shalbuzdag , 41°17′27″N, 47°49′11″E, shale scree, 2745 m a.s.l., parasitizing on Cirsium pugnax , 27 June 2023, S. A. Svirin (holotype LE, isotypes KTC) ; Dagestan, Dokuzparinskiy Distr., vicinity of Kurush, W slope of Mt. Nesindag , 41°15′10″N, 47°48′15″E, screes, 2765 m a.s.l., parasitizing on Cirsium tomentosum , 16 July 2021, R. A. Murtazaliev (paratypes DAG!, KTC!) ; Dagestan, Agulskiy Distr. , 5 km NNW Chirag, 41°52′47″N, 47°23′25″E, shale scree, 2400 m a.s.l., parasitizing on Cirsium pugnax , 25 June 2023, A. V. Fateryga & S. A. Svirin (paratypes KTC!, PHEO!, YALT!) .

Description:―Plant (30–)36–40(–45) cm tall, ± pink, pale brown to more or less pinkish (aerial part) and whitish to yellowish (underground part) and, sometimes, orangish-yellow at the base of stem. Stem simple (the underground part comprising more than half of the stem and a little thicker), thick, (9.0–)10.0–12.5(–14.0) mm in diameter in the upper part, 10.0–16.6(–22.2) mm in the middle and very slightly widening towards the base, (11.0–)15.0–23.3(–24.5) mm; scarcely bulbous at base; slightly striate (clearly striate when dry); densely glandular-pubescent in the entire aerial part, white glandular hairs with ± pale yellowish gland. Basal leaves (17.8–)20.0–24.6(–33.0) mm × (6.0–)8.3–11.0(– 12.5) mm, ovate-lanceolate to lanceolate, sometimes abruptly enlarged at the base, dense (especially towards the foot), glabrous abaxially. Upper leaves (15.0–)17.0–22.2(–25.9) mm × (5.0–)6.0–10.5(–12.2) mm, triangulate-lanceolate to lanceolate, sparse, usually erect, pale yellowish to pale brown, changing early to brownish (when drying), especially at the apex, glabrous abaxially. Inflorescence (9.0–)13.7–18.4(–21.3) cm × (3.2–)3.9–4.2(–4.5) cm, cylindrical to slightly ovate, densely glandular-pubescent (white hairs with ± pale yellowish gland), usually shorter than the remaining stem (sometimes it is almost the only aerial part); (15–)24–30(–32)-flowered, ± dense, rarely lax. Bracteoles absent. Flowers erect (ca. 30–38º with the axis). Bracts (13.0–)16.0–20.6(–21.3) mm × (3.2–)5.0–10.6(–11.3) mm, shorter or rarely almost equal to the corolla, ovate-lanceolate to lanceolate, dark pink to pale yellowish-brown, with dense white glandular hairs (later brown and ± glabrescent, when dry, especially towards the apical part). Calyx (8.2–)10.0–15.6(– 20.0) mm long, only (1.7–)2.8–4.4(–5.0) mm wide at the widest point, usually shorter than half of the corolla tube; segments simple, entire, narrowly lanceolate, sometimes almost filiform; long acuminate teeth with a ± ovate base; segments free, clearly separate; densely glandular-hairy; segments of calyx dark pink, pale pink to pale pinkish-brown or pale yellowish-brown. Corolla (21.5–)25–29(–31.0) mm long, (8.9–)10.0–11.3(–12.0) mm in diameter in the central part; tubular-infundibuliform, widening at the throat, usually strongly inflated above the insertion of the filaments, and strongly constricted below; the dorsal line ± evenly curved at the base, straight at the middle part and bent forward at the apex; externally densely or very densely glandular-pubescent with white glandular hairs (± yellowish glands); corolla pink, pale pinkish-brown, pale pink to pale brown, with darker veins. Upper lip slightly emarginate, with two rounded lobes, porrect first and patent or little curved upward (rarely deflexed) later, sparsely to densely glandular-hairy also in the inner part. Lower lip with three obovate or ± rectangular to ovate-triangular lobes, erose or irregularly crenulate-denticulate on margins and sparsely glandular-hairy also in the inner part and margins. Stamen filaments obliquely inserted and slightly widened at base, adaxial filaments (3.4–) 5–6 mm above the corolla base, abaxial at (2.3–)4.0– 4.5 mm. Filaments (15.0–)15.5–18.0 mm long, 1.4–2.0 mm wide, geniculate, densely villous in the base to middle part; not glandular, white hairs 0.6 mm long, upper part with dense short, usually ca. 0.15–0.20 mm, white with pale yellow glands, glandular hairs; filaments white to pale pink. Anthers 2.6–2.8 mm long, ca. 1.5–2.0 wide, oblongoid, mucronate (mucro whitish), pale brown; basally and along ¾ of suture distinctly and numerously hairy. Ovary 6.6–8.8 mm × (2.8–) 3.3–4.8 mm, glabrous or with very sparse white glandular hairs above, pale yellow, basally orangish (gynoecial nectary). Style (15.5–) 17–18 mm long, with very sparse (more abundant and dense on the upper part) short glandular hairs, ca. 0.15–0.20 mm long, style pale brown to pale pink. Stigma distinctly ovately bilobed, lobes yellow, ± verrucose. Seeds usually oblongoid; seed coat reticulate with polygonal shallow cells, which range from more or less isodiametric to irregular; seed coat is pitted. Pollen inaperturate, spheroidal.

Distribution and habitat:―So far, Orobanche dagestanica has been found in three localities (requires further research) and is probably endemic to the Greater Caucasus. The localities of the newly-described species are situated on either west or north-east facing slopes, at an elevation of 2400–2765 m ( Fig. 3 ). Two localities in the Dokuzparinskiy District belong to the Samur River basin: Mt. Shalbuzdag and the west slope of Mt. Nesindag (in the Ragdanchay River valley near the border with Azerbaijan). The locality in the Agulskiy District is situated in the Chiragchay River valley, the Gyulgerychay River basin. All three localities represent shale screes with sparse alpine vegetation (coverage about 10–50%). The most abundant plant species occurring there are Lophiolepis horrida , L. isophylla , Jurinea moschus (Hablitz) Bobrov (all Asteraceae ), Heracleum grandiflorum Steven ex M. Bieb. ( Apiaceae ), Alliaria taurica (Adam) V.I. Dorof. ( Brassicaceae ), Silene lacera (Steven) Sims ( Caryophyllaceae ), Betonica nivea Steven ( Lamiaceae ), and Nonea versicolor (Steven) Sweet ( Boraginaceae ).

Phenology:―Flowering period June–July, fruiting July–August.

Ecology:―Parasitic on Lophiolepis horrida [= Cirsium pugnax Sommier & Levier ] and, sometimes, on L. isophylla [≡ C. isophyllum (Petr.) Grossh. ; = C. tomentosum C.A. Mey. , nom. illeg.] ( Asteraceae ) ( Fig. 3 ). Two species of floral visitor were recorded on O. dagestanica : Lasioglossum punctatissimum (Schenck, 1853) ( Hymenoptera : Halictidae ), a single female, and Dolichovespula sylvestris (Scopoli, 1763) ( Hymenoptera : Vespidae ), also a single female.

Etymology:―The epithet ‘ dagestanica ’ derives from the place of description: Dagestan ( Russia). The word ‘Dagestan’ (Turkish and Persian origin) also means ‘land of the mountains’, and the new species occurs in the mountains only.

Conservation:―Two of the three habitats of the new species are situated within Samurskiy National Park (Mt. Shalbuzdag and the west slope of Mt. Nesindag). The population is small (about 100 individuals were examined across all localities). The locations of the new species are quite stable; no overgrazing was recorded.

Phylogenetic studies:―In the trees inferred for ITS and trnL-trnF sequences ( Fig. 4 ), the new species forms a common clade with O. cicerbitae (Uhlich & Rätzel) Tzvelev (2015: 210) , O. krylowii Beck (1881: 309) , O. inulae Novopokrovsky & Abramov in Novopokrovsky (1950: 323), O. mlokosiewiczii Piwowarczyk et al. (2017b: 125) , O. arpica Piwowarczyk et al. (2018c: 66) , and, in the ITS tree alone, O. lycoctonii Rhiner (1892: 133) , indicating high affinity to these species. However, it is clearly separated from them, with bootstrap support values of 96 and 100, confirming its distinctness.

Figures

FIGURE 1. Orobanche dagestanica.A. Habit. B. Flower, front view. C. Flower, lateral view. Illustration by Jolanta Urbanik.

FIGURE 2. Orobanche dagestanica. General habit.A–D. Variability of inflorescences. E. Flowers in lateral view and a long-section, with visible upper style, stigma and stamens. F. Excavated parasite, two entire specimens attached to the roots of their host, Lophiolepis horrida. G. Stems with scale leaves. Photos by S. Svirin (A, C, D, E, F), R. Murtazaliev (B, G).

FIGURE 3. Orobanche dagestanica. Representative habitats and hosts. A, B. Alpine shale scree, slopes of Mt. Shalbuzdag, Greater Caucasus, Dagestan, Russia (type locality). C. Host plant Lophiolepis horrida with the parasite, Chiragchay River valley. D. Excavated host L. horrida with attached parasites. Photos by S. Svirin (A, B), A. Fateryga (C, D).

FIGURE 4. Rooted Maximum Likelihood phylogenetic trees constructed for ITS (upper) and trn (bottom) sequences. Phelipanche purpurea was used as an outgroup. Numbers near branches show bootstrap values. The bars represent the amount of genetic change (nucleotide substitutions per site).