Orobanche javakhetica Piwow., Ó. Sánchez & Moreno Mor., 2018

Piwowarczyk, Renata, Pedraja, Óscar Sánchez, Moral, Gonzalo Moreno, Denysenko-Bennett, Magdalena, Góralski, Grzegorz & Kwolek, Dagmara, 2018, Orobanche javakhetica (Orobanchaceae): a new species from the Caucasus (Armenia), Phytotaxa 360 (2), pp. 135-144 : 137-142

Orobanche javakhetica Piwow., Ó. Sánchez & Moreno Mor. , sp. nov. ( Figs. 1 , 2 )

Type: — ARMENIA. Shirak prov.: Javakheti range (Lesser Caucasus), E of village Ghazanchi, subalpine meadow, NW exposure, 2225 m, 22 July 2017, R. Piwowarczyk s.n. (holotype KTC!).

Description: —Plant holoparasitic, achlorophyllous, (20–)25–30(–35) cm tall, pale yellow, pale dirty pink. Stem simple, ± slender (3.5–)4.0–5.0(–7.0) mm in diameter in the upper part, (4.0–)5.0–6.0(–8.0) mm in the middle, slightly widening towards the base, (5–)6–7(–12) mm; slightly bulbous at base; slightly striate (clearly striate when dry); densely glandular pubescent in the upper part, with whitish or pale orange glandular hairs (0.2–) 0.4–0.7 mm; stem pale white-yellow or rarely pale yellow-brown (brown when dry). Basal leaves (15–)16–18(–20) mm × (3.0–)3.5–4.0(–6.0) mm, lanceolate, glabrous abaxially, or shortly ciliate at the edge with hairs ca 0.3 mm. Upper leaves (12–)15–16(–18) mm × (3.5–)4.0–5.0(–6.0) mm, narrowly lanceolate to lanceolate, becoming sparse above, pale yellow-brown, dirty pinkish, pinkish-brown, changing early to brown when drying, especially at the top; sparsely glandular- and nonglandular pubescent, especially at the edge, with hairs 0.2–0.4 mm. Inflorescence (5.0–)9.0–12(–14) cm × (2.5–)3.0– 3.5 cm, cylindrical to slightly ovate, shorter than the remaining stem; (17–)20–28(–40)-flowered, ± dense. Flowers are erecto-patent and medium sized. Bracts (11–)13–14(–16) mm × (4.0–)4.5–5.0(–6.0) mm, shorter or rarely equal to the corolla, broad ovate-lanceolate, with dense white or pale yellow glandular hairs, 0.3–0.4(–0.6) mm long, clearly darker than the leaves, pinkish-brown, violet-brown, brown. Bracteoles absent. Calyx (7–)8–9(–11) mm long, (1.0–)2.0–2.5(–3.0) mm wide at the widest point, shorter than half of the corolla tube; two segments, free, clearly separate, simple, entire, narrow, with teeth long, acuminate almost filiform at apex and with bases gently ovate, pale pink, pale yellow-brown, with dense glandular-hairy, hairs ca 0.2–0.4(–0.6) mm, white or pale yellow. Corolla (15–)18–19(–21) mm long, (5–)6–7(–8) mm in diameter in the central part; tubular to narrowly campanulate (slightly widening towards the mouth), usually strongly inflated above the insertion of the filaments, and strongly constricted below; the dorsal line slightly curved in the lower part, less curved or straight in the middle part and ± flexed forwards or straight at the apex, externally glandular-pubescent with white or pale yellow (in dry form with orange glands) glandular hairs of (0.1–) 0.2–0.3 mm, more or less abundant, hair cover slightly denser at upper lip; corolla pale yellow-pink, white-yellow, yellowish-white, frequently pinkish at the apex (lobes) and veins, with dirty white, pale pink or pale yellow veins; upper lip slightly emarginate, with two short broad lobes, usually facing downward (rarely raised when dry), sparsely glandular hairy also in the inner part, hairs ca (0.2–) 0.3–0.4 mm; lower lip with three oval, or ± rectangular lobes, central lobe slightly larger than lateral lobes, lobes irregularly dentate on margins, lobes sparsely glandular hairy also in the inner part. Stamens obliquely inserted, adaxial at 4.0– 4.5 mm above the corolla base, and abaxial at 3.5–4.0 mm, all slightly widened at base. Filaments 13–15 mm long, 1.5 mm wide, white to pale yellow or pale pink, clearly geniculate, densely villous; from base to ± middle part, hairs (0.3–)0.4–0.5(–0.6) mm long, not glandular, white, upper part densely glandular-pubescent, usually ca 0.1–0.2 mm long, short, white with orange glands. Anthers 2.0– 2.5 mm long, ca 1.0– 1.5 mm wide, oblongoid, mucronate, pale brown; basally and along ¾ of suture distinctly and numerous hairy (ca 0.3–0.5 mm). Ovary 7–9 mm × 3.5–4.0 mm, glabrous, whitish, pale yellow, pale pink; lateral opening by two longitudinal slots. Style 10–12 mm long, pale yellow to whitish, glabrous except below stigma, here with very sparse short and glandular hairs (these ca 0.1–0.2 mm long and more abundant, conspicuous and dense on the upper part). Stigma bilobed, lobes elongated-spherical to ovate and ± flattened, with numerous warts (orange when dry) on the lobes, and yellow or bright yellow. Seeds ovoid or oblongoid; seed coat reticulate with shallow polygonal cells, which range from more or less isodiametric or irregular; seed coat is pitted. Pollen inaperturate, spheroidal.

Distribution and habitat: ―The species is until now only known from the type locality, located in the northwestern part of Armenia, in the Shirak province, 30 km NNE of Gyumri, 4 km ESE of village Ghazanchi, in the SW edges of Javakheti range. Orobanche javakhetica grows on the WSW slope of Ampasar Mt. (3046 m), with NW exposure, 2225 m a.s.l., in a subalpine meadow. The community was dominated by the Lomelosia caucasica , Stachys macrantha , and Cephalaria giganthea ( Fig. 3 ).

The Javakheti Highland is located in the central part of the Lesser Caucasus, in the border region between Georgia and Armenia, and is characterized by an almost treeless region, plateaus, intermontane valleys and volcanic ranges with separated central volcanoes and volcanic domes (Lebedev et al. 2017). The Javakheti range is a medium- to high-elevation mountainous area from 1500 m to the highest elevations ca 3300 m in Georgia (Didi-Abuli Mt) and 3196 m in Armenia (Achkasar Mt), characterized by mountain steppes, wetlands, subalpine and alpine meadows, often used for grazing, with lakes of tectonic and volcanic origin. The climate is harsh, windy, and continental with severe winters, cool summers and high rainfall. The predominant type of soil is chernozem. Geologically this neovolcanic area consists in the high mountain range of pliocene andesite, dacite, and rhyolite, as well as in the lower parts of the highlands of pliocene volcanic rocks, such as basalt and andesite ( Lebedev et al. 2007).

Phenology: ―Flowering in second half of July, fruiting in August.

Ecology: ―Parasitic on Lomelosia caucasica (M. Bieb.) Greuter & Burdet in Greuter & Raus (1985: 73) (syn. Scabiosa caucasica M. Bieb. ) ( Dipsacaceae ) ( Fig. 3 ), host attachment was verified. This species is native to the Caucasus, northeastern Turkey, and northern Iran. It is possible that the new species may occasionally also parasitize Stachys macrantha (K. Koch) Stearn ( Betonica macrantha K. Koch ), because in some places the roots grow so densely that such suspicion existed.

Etymology: ―The epithet ‘ javakhetica ’ derives from the name of the Javakheti mountain range (Dzhavakheti range), where the new species was discovered.

Conservation: ―The locality of new species lies outside but very close to the SW border of the protected areas of the Arpi Lich National Park. The population is small (ca. 20 individuals), habitats are quite stable, however in the neighboring area, grazing is too intense.

Phylogenetic studies: ―Bayesian and Maximum Likelihood trees generally show similar relationships between taxa, later description is based on Bayesian trees ( Figs. 4 , 5 ) with one exception mentioned below. Both types of sequences (ITS and trnL-trnF) show clear differences between O. javahketica and other species used in the study with a strong posterior probability support (1.0). The trnL-trnF trees show that O. javakhetica is closest to O. gracilis . Although these two species form a common branch with strong support (1.0), the long branches show that the differences between them are significant. Together they form a sister clade to section Orobanche (except O. gracilis ). On the Maximum Likelihood tree, these two species are slightly similar to O. grenieri and O. cernua , however with not significant support (41). On the ITS trees, O. javakhetica is separated from O. gracilis (although there are weak probability/bootstrap values on nodes separating these species) and forms a common branch, however also with weak support (0.78), with O. grenieri , O. cernua and O. coerulescens .

Discussion: ―The newly-described species is morphologically very characteristic and different from other known Orobanche . So far, Lomelosia caucasica has not been confirmed as the host species of Orobanche s. l. However, species from the genera Scabiosa and Knautia ( Dipsacaceae ) have been mentioned as one of the hosts of O. pancicii and more rarely of O. reticulata (both belonging to the O. subsect. Glandulosae Teryokhin), but these species do not correspond with the newly described species, which, e.g., shows the corolla without the typical red glandular hairs of this section. Another Dipsacaceae , the species of the genus Cephalaria , seems to be the host-plant of O. grossheimii (O. subsect. Curvatae (Beck) Piwow., Ó. Sánchez & Moreno Mor. [O. subsect. Orobanche sensu Teryokhin et auct. pl.]). This species is very different in all aspects, both morphological ( Novopokrovskij & Tzvelev 1958; Tzvelev 2015) and genetic ( Carlón et al. 2008: 13 fig. 2 (ITS tree)). This same genus Cephalaria has also been cited as a doubtful host of the above-mentioned O. reticulata ( Tzvelev 2015) .

Phylogenetic studies confirm that O. javakhetica is distinct from other studied species. It seems to be separated both from the clade representing the subsect. Orobanche (except O. gracilis ) as well as species belonging to the subsect. Inflatae Beck ( O. grenieri , O. cernua and O. coerulescens ). However, trees based on trnL-trnF sequences show a common branch with O. gracilis (O. subsect. Cruentae Teryokhin), but the difference between these species is not significant enough to indicate a close phylogenetic relation. ITS trees also show separation of O. javakhetica from other Orobanche (with weak similarity to subsect. Inflatae ) but do not present a clear similarity to O. gracilis . Such a difference in the relation between O. javakhetica and O. gracilis in two types of sequences may be caused rather by the fact that O. gracilis , as was shown in our previous paper ( Piwowarczyk et al. 2018a), has an unclear phylogenetic position. The uncertainty of the phylogenetic relationship of O. javakhetica to other species (and subsections) of Orobanche will be probably clarified in the future in wider phylogenetic studies when some new related species may be found.

Although the phylogenetic relationships visible on trnL-trnF trees seem to indicate some relation, though not a close one, with species with dark red coloration at least on the inner side of the corolla as in the case of O. gracilis (O. subsect. Cruentae Teryokhin), the morphological characters and host-plants do not support this relationship, which is also visible on ITS trees. Morphologically, there seems to be some similarity to the O. subsect. Orobanche (O. trib. Galeatae sensu Beck), but this is restricted to the corolla being bent forward at the apex, which may vaguely resemble the species of this section. However, the rest of the characters, such as habit and colour, dense inflorescence, calyx segments (free, clearly separate, simple, entire, narrow), corolla tubular to narrowly campanulate (slightly widening towards the mouth) and stigma cone ± flattened yellow lobes, are clearly different from species in this section.

Despite what was said at the beginning of the discussion of the newly-described species, some morphological similarity may exist with other species from Orobanche subsect. Curvatae (Beck) Piwow., Ó. Sánchez & Moreno Mor. , particularly with species of the Orobanche series Krylowianae Piwow., Ó. Sánchez & Moreno Mor. ( Piwowarczyk et al. 2017a), this similarity is observable, e.g., in the habit and yellowish colour of the plant, the ± strong narrowing of the corolla in the place of insertion of the filaments, and the colour and morphology of the stigma. However, O. javakhetica from these species differs very clearly in the morphology of flowers and host (see key). Of course, a more thorough and systematic exploration of the Caucasus region in search of new populations will be helpful to confirm our concept and the phylogenetic relationships of this species.

Identification key (modified from Frajman et al. 2013 and Piwowarczyk et al. 2017a)

1 Plant always yellowish or whitish; upper lip ± porrect (continuing the dorsal line of the corolla tube) or flexed forwards............. 2

- Plant usually strongly pigmented, rarely yellowish-white; upper lip erect or recurved..................................................................... 3

2 Corolla tubular to narrowly campanulate (slightly widening towards the mouth); dorsal line ± flexed forwards or straight at the apex; on Lomelosia caucasica ( Dipsacaceae ) .............................................................................................................. O. javakhetica

- Corolla broadly tubular-campanulate to campanulate (conspicuously widening towards the mouth); dorsal line ± porrect at the apex; on other species......................................................................................................................................................................... 4

4 Bracts usually longer than the corolla; calyx segments 10.4–16.8 × 3.5–7.8 mm, usually unequally bidentate; style glabrous or nearly; on Aconitum lycoctonum ( Ranunculaceae ) .......................................................................................................... O. lycoctoni

- Bracts usually shorter than the corolla; calyx segments 6–15 × 1.5–5 mm, usually entire or more unequally bidentate; style hairy; on other species .................................................................................................................................................................................. 5

5 Calyx segments 10–15 × 3–4 mm, c. 3/4 corolla length, lanceolate; on Inula sp. ( Asteraceae ).......................................... O. inulae

- Calyx segments 6–12 × 1.5–2.5 mm, c. 1/2–2/3 or less corolla length, ovate-subulate or ovate-lanceolate; on other species ......... 6

6 Corolla 17–21 mm, tubular; dorsal line gently and regularly curved (but straight near the apex); lobes with finely eroded-denticulate margin; on Thalictrum minus ( Ranunculaceae )................................................................................................................. O. krylowii

- Corolla (17–)20–23(–25) mm, tubular to campanulate; dorsal line slightly or strongly curved (but ± deflexed at the apex); lobes with irregularly dentate or finely eroded-denticulate and glandular margin; on other species .......................................................... 7

7 Corolla (17–)20–23(–25) × (7–)10–12(–14) mm, usually campanulate or more rarely tubular-campanulate, dorsal line slightly curved (but straight at the apex); lobes oval or rectangular to triangular, with irregularly dentate margin; on Aconitum cymbulatum ( Ranunculaceae )……………………………………………………. ..................................................................... O. mlokosiewiczii

- Corolla (21–)22–23(–25) × (6.8–)7.0–7.8(–8.3) mm, tubular, strongly curved (but ± deflexed at the apex); lobes spathulate rounded, with finely and irregularly denticulate and glandular margin; on Prenanthes petiolata ( Asteraceae )............................ O. cicerbitae

3 Corolla with distally straight dorsal line, with a distinctly flattened subapical area; lower lip cruciform, with concave, spathulate, very divergent lobes; on Centaurea and Echinops ( Asteraceae )........................................................................................... O. kochii

- Corolla with regularly curved dorsal line; lower lip with less divergent, elliptic or rounded and flat to convex lobes..................... 8

8 Corolla variably (orange, reddish, yellow, yellowish-brown), but usually vividly pigmented; filaments hairy almost to the apex; on Petasites sp. ( Asteraceae ) ....................................................................................................................................................... O. flava

- Corolla brownish, purple or reddish to yellowish brown, rarely yellow, but usually feebly pigmented; filaments hairy at most in its lower two thirds.................................................................................................................................................................................. 9

9 Plants up to 85 cm, tall and stout; inflorescences long, cylindrical, often covering the upper two thirds of the stem; corolla with dorsal line regularly curved, sometimes more or less deflexed at the apex; upper corolla lip shallowly emarginate; mainly on Centaurea ( Asteraceae ) ............................................................................................................................................... O. elatior s. str.

- Plants up to 60 cm, usually shorter and more slender, with relatively narrower stems; oval inflorescences, dense, at most covering the upper half of the stem; corolla with regularly and strongly curved dorsal line, but somewhat straight at the apex; upper corolla lip more deeply and distinctly emarginate; on Apiaceae (mainly on Peucedanum , Seseli ) ............... O. alsatica (incl. O. bartlingii )

Figures

FIGURE 1. Orobanche javakhetica. A. Plant. B. Flower, side view. C. Flower, front view. D. Open corolla and androecium. E. Bract. F. Leaf. G. Calyx. H. Anther. I. Stigma. J. Gynoecium. Illustration by Jolanta Urbanik.

FIGURE 2. Inflorescences and general habit of Orobanche javakhetica. Photos by Renata Piwowarczyk.

FIGURE 3. Habitat and host. A. Habitat with the dominant host species of Lomelosia caucasica. B. Flower of host species. Photos by Renata Piwowarczyk.

FIGURE 4. Rooted Bayesian phylogenetic trees constructed for ITS sequences.As an outgroup, Phelipanche ramosa was used. Numbers near branches show Bayesian posterior probabilities. The bar represents the amount of genetic change (nucleotide substitutions per site).

FIGURE 5. Rooted Bayesian phylogenetic trees constructed for trnL-trnF sequences. As an outgroup, Phelipanche ramosa was used. Numbers near branches show Bayesian posterior probabilities. The bar represents the amount of genetic change (nucleotide substitutions per site).