Orobanche laxissima Uhlich & Rätzel

Piwowarczyk, Renata, Pedraja, Óscar Sánchez, Moral, Gonzalo Moreno, Fayvush, George, Zakaryan, Narine, Kartashyan, Nune & Aleksanyan, Alla, 2019, Holoparasitic Orobanchaceae (Cistanche, Diphelypaea, Orobanche, Phelipanche) in Armenia: distribution, habitats, host range and taxonomic problems, Phytotaxa 386 (1), pp. 1-106 : 78-83

13. Orobanche laxissima Uhlich & Rätzel in Rätzel & Uhlich (2004: 194). TYPE:— RUSSIA (holotype): “in Caucaso boreo-occidentali (Adygaea) prope pagum Novoprokhladnoye, ca. 700 m a. s. l., in fruticetis, leg. S. Rätzel, 30.06.2002 n. 2334” (B); isotypes (Herb. Rätzel n. 2333 et 2335). Figs. 52–53 .

Supplementary description: —Plant (10–)25–40(–100) cm high, purple, violet, reddish, from dark to pale pink, dirty pink, pale-yellow, dirty yellow and ochre. Haustoria are very numerous, dirty orange, or rarely light brown, to dark purple. Stem simple, (3–)4–5(–7) mm in diameter in the middle part, slightly widening towards the base, up to 6‒8 mm; slightly bulbous at the base; slightly striate (clearly striate when dry); densely glandular-pubescent in the upper part, with white or, rarely, pale yellow hairs 0.3–0.5(–1.0) mm; stem purple, reddish, pale or dark dirty pink, pale violet or rarely pale yellow, ochroleuca, ochre, light brown, usually lighter in the lower part. Basal leaves 16–18(–24) × 6–7(–11) mm, ovate-lanceolate (triangular) to lanceolate, imbricate, glabrous abaxially but shortly ciliate at the edge with hairs ca. 0.3 mm. Upper leaves 15–16(–20) × 5–6 mm, narrowly lanceolate to lanceolate, becoming sparse above, more or less erect, dark purple or brown, changing early to dark brown, especially at the top; with a broad base, densely glandular-pubescent abaxially, with short hairs up to 0.3 mm. Inflorescence (4–)14‒16(–36) × (2–)2.5‒3(–4.5) cm, cylindrical to slightly ovate, shorter than the remaining stem; (10–)21(–33)-flowered, usually sparse, at the top denser, especially when young. Bracteoles are absent. Bracts (14–)17(–22) × (4–)6(–10) mm, shorter or equal to the corolla, narrowly lanceolate, with white or pale yellow glandular hairs, 0.3–0.5(–1) mm. Calyx (6–)13–15(–19) mm long, (2–)4–5(–7) mm wide at the widest point, shorter than the corolla tube, of up to half a corolla; segments simple or 2-toothed, sometimes with 4 teeth, underdeveloped, entire, narrowing to the apex; long very narrowly acuminate teeth with a gently ovate base; segments free, clearly separate; dense glandular-hairy at base, hair forming sparse cover at the edge and the apex, hairs short ca. 0.3–0.5 mm, purple, pale pink or yellow; lower parts of calyx pale yellow, pink, violet or purple with the tip, 1- or rarely 2-veined. Corolla (16–)22–24(–31) mm long, 3–4 mm in diameter in the central part; erect, purple, dark or light pink, rarely dirty yellow, light brown, lighter at the ends of the lips thin hem of the outer side, usually brighter in the middle, pale gold or creamy with purple veins, throat is usually not wide open and lips curled there, sometimes wide open with lips that curl outwards, usually inside more lightly coloured; the dorsal line slightly curved, sometimes almost horizontal, with umbonate on the upper lip, only slightly inflated at base; externally glandular-pubescent with white or pale pink (in dry form, orange) glandular hairs of 0.3–0.5(–0.8) mm, more or less abundant, hair cover slightly denser at upper lip; inside glabrous or rarely less hairy; corolla basally yellowish-white, upper parts pale pink with violet or dark pink veins; lips unevenly serrated, with lighter margins and yellow-orange glandular hairy, upper lip with two short, broad lobes, emarginated, erect or rarely patent; lower lip with three oval lobes, central lobe slightly larger than lateral lobes, irregularly dentate on margins. Stamen filaments obliquely inserted, adaxial filaments 2–3 mm above the corolla base, abaxial at (1.5–)2.1(–2.5) mm, slightly widened at base, 13–16(–18) mm long. Filaments clearly geniculate, densely villous in the base to 1/3 part; non-glandular and glandular hairs up to (0.3–)0.5–1.0(–1.2) mm long, upper part with short, white, or yellow glandular hairs; filaments white to pale to dark yellow, sometimes pale pink. Anthers 2.0– 2.2 mm, dark brown, paler when dry; glabrous with sparse short glandular hairs (ca. 0.1–0.3 mm) located at the line of fusion. Ovary (7–)10(–14) × (3–)3.8(–4) mm, shorter than style, elliptic, glabrous or with very sparse white glandular hairs from the style ca. 0.1–0.3 mm above; lateral opening by two longitudinal slots. Style (13–)15(–16) mm, with glandular hairs, denser from the stigma side, pink, purple, rarely orange, pale to dark yellow. Stigma bilobed, with numerous warts (orange when dry) on the lobes and dark pink, violet to purple; dark pink, or more rarely orange, pale to dark yellow; sometimes purplish or dark pinkish and conspicuously separate from the yellow style; stigma are widely spaced.

Distribution: —In the northeastern (Tavush prov.) and southeastern (Syunik prov.), rarely central parts (Kotayk prov.) ( Fig. 54), in regions where forest complexes occur ( Figs. 2–3).

General distribution: —The Caucasus Mountains and Transcaucasia; especially Russia, Georgia, Azerbaijan, N.E. Turkey ( Rätzel & Uhlich 2004, Rätzel et al. 2013, Piwowarczyk & Tatanov 2013, Piwowarczyk in Nobis et al. 2018b).

Habitat: —Moist, shady or semi-shady places in deciduous forests, especially hornbeam-oak, hornbeam-beech, roadsides on the edge of the woods and roads, scrub, parasitic on roots of woody plants in the submontane and montane zone ca. 700‒1800(2000) m.

Hosts: —Polyphagous root parasite of trees and shrubs from Betulaceae , Oleaceae , Fagaceae , like Fraxinus excelsior L., Fagus orientalis Lipsky , Carpinus betulus L., C. orientalis Mill. In the remaining area of the Caucasus also on Cornaceae and Aceraceae . It is a rare phenomenon of parasitism for Orobanche species to be on roots of trees, characterized by generally narrow distribution ranges, and are most often endemic.

Phenology: —Flowering (May) June to July, fruiting July–August.

Conservation status: —Vulnerable (VU) – B 1 ab (iii) + 2 ab (iii). Endemic to the Caucasus. EOO is less than 20,000 km 2, severely fragmented, existing at no more than 10 locations (8 locations in 3 floristic regions), AOO is less than 2000 km 2, severely fragmented, existing at no more than 10 locations. Individuals in populations are usually numerous, from 10 to even over several hundred shoots, often a few, or a dozen in one clump (e.g. near Lichk waterfall). Limiting factors are restricted EOO and AOO, loss/degradation of habitats caused by changes in forest habitats.

Notes: — Orobanche laxissima is a very polymorphic species and has a very variable coloration, pink, yellow or deep purple flowers with yellow colouring inside the corolla, shoots deep pink, violet or purple, often yellow or light yellow ( Fig. 52 ). It seems that O. laxissima can be confused by an inexperienced researcher with O. owerini and O. crenata , especially in the herbarium materials without details about the host.

O. laxissima it seems to be very similar morphologically to O. transcaucasica described from the Shemackha region in Azerbaijan by Tzvelev (1957), from forest and scrub at about 800 meters, without specifying the host, as a species endemic to E. Transcaucasia. Moreover, in 2013 O. laxissima was reported at several locations from Azerbaijan ( Rätzel et al. 2013). Despite this, Teryokhin ( Teryokhin et al. 1993) considers O. transcaucasica to be a doubtful species, having no distributional data and specific host-plant. At the collection site of the type specimen of O. transcaucasica, Teryokhin found only O. crenata , in a hornbeam-oak forest [attention should be paid to the listed habitat in the context of the hosts], parasitising Corylus avellana . However, that host clearly indicates that it may not be a typical O. crenata , which parasitises herbaceous plants mainly from Fabaceae , and no mention was made of a host tree or shrub for this species. Only Teryokhin et al. (1993) reported that O. crenata parasitises trees like Corylus L. and Fraxinus L, as well as herbaceous species of the Fabaceae . The specimen type (BAK) of O. transcaucasica from the locus classicus from Azerbaijan is somewhat damaged ( Fig. 55 ). So, it must remain an open question as to whether O. transcaucasica and O. laxissima belong to the same species and O. laxissima should be treated as a synonym of O. transcaucasica . Furthermore, Rätzel and Uhlich (2004) mistakenly assigned O. laxissima to the O. subsect. Galeatae Teryokhin (O. trib. Galeatae sensu Beck). Morphologically the species clearly belongs to the O. subsect. Speciosae Teryokhin (O. trib. Speciosae sensu Beck ).

Taxonomic Note: — Orobanche transcaucasica Tzvelev in Komarov (1958: 686). Type:— AZERBAIJAN (holotype): Shemackha Region (environs of the village of Sharadil (Seredil) in mixed forest (Carpineto-Quercetum) at nearly 800 m above sea level [(orig.: distr. Schemacha, pr. p. Scharadil, in silva mixta (Carpineto-Quercetum) ca. 800 m alt.], 06.06.1941, leg. I. Schchiponova, 06.06.1941 (BAK 0-0000063!) ( Fig. 55 ) ( Tzvelev 1957: 582; Novopokrovskij & Tzvelev 1958: 97, 686).

Specimens examined: — ARMENIA. Kotayk prov.: Agveran, 11 July 1971, N.Karapetyan (ERCB) [as O. crenata by T. Tsaturyan]; Arzakan, 1970, S. Grigoryan (ERCB) [as O. crenata ]; Hrazdan distr., Tsahkunyats range, N slope, opposite to village Meghradzor, 1800 m, 24 July 1982, N.S. Khandjian (ERE) [as O. caryophyllacea by S. Grigoryan]; Tsakhkadzor, forest, 2300 m, 4 July 2017, N. Kartashyan & N. Zakaryan (ERCB); Syunik prov.: Lichk S, SE, road to waterfall, woody thicket on the slope, on Fraxinus , 39°03’03”N, 46°10’52”E, 1705 m, 39°02’48”N, 46°10’25”E, 1740 m, 17 June 2017, R. Piwowarczyk (ERCB, KTC); behind the Meghri river towards waterfalls, mixed forests and scrubs, on Fraxinus , 39°02’46”N, 46°10’23”E, 1750–1760 m, 17 June 2017, R. Piwowarczyk (ERCB, KTC); E of Shishkert, forest, edge of the forest on the slope and roadsides, on Carpinus and Fraxinus , 39°03’54”N, 46°23’16”E, 1520 m, 39°04’03”N, 46°22’29”E, 1590 m, 39°03’49”N, 46°23’08”E, 1515 m, 18 June 2017, R. Piwowarczyk (ERCB, KTC); Goris distr., monastery between Tatev and Anapat, right slope of the Vorotan valley, 13 July 1967, V. Manakyan (ERE) [as O. crenata by S. Grigoryan]; Tavush prov.: ca. 17 km SSE of Noyemberyan, from Acharkut into the valley direction SW, side track from 41°01’56”N, 45°04’11”E to 41°02’02”N, 45°03’52”E, 795–855 m, 41°1’59”N, 45°4’2”E, 26 June 2008, G. Fayvush, K. Tamanyan, K. Kugler & E. Vitek (W, ERE, PAL, PE) [as O. crenata by G. Domina]; W of Acharkut, NNW of Samson bridge, edge of forest on the slope, on Fraxinus , 41°01’52”N, 45°04’03”E, 798 m, 26 July 2017, R. Piwowarczyk (ERCB, KTC); W part of Acharkut, forest on the slope, 41°02’04”N, 45°04’46”E, 765 m, 26 July 2017, R. Piwowarczyk (ERCB, KTC); Apaga resort, W of Yenokavan, in shaded forest, 40.913, 45.077, 11 July 2018, phot. T. Baas, A. Hos & Ans Den Haan; between Jujevan and Noyemberyan, side road to Lorut, forest, on Fagus , 41°08’06”N, 44°59’49”E, 1185 m, 26 July 2017, R. Piwowarczyk (ERCB, KTC); Noyemberyan, 10 July 2018, phot. K. Nilsen; Idjevan distr., Laligeh vil. [Lusadzor vil.], forest, 20 June 1959, Ja. Mulkidjanyan (ERCB) [as O. crenata by T.G. Tsaturyan]; Noyemberyan distr., Lambalu village [Bagratashen vil.], Sadakhlo forestry, Carpinus orientalis forest [41°12’18”N, 44°50’28”E] 22 July 1960, V. Avetisyan & E. Gabrielyan (ERCB) [as O. crenata by T.G. Tsaturyan]; Zikatar, in Fagus forest, 41.12492 -44.92839, 1221 m, 10 July 2018, phot. Ans Den Haan; Idjevan distr., Sevkar, on the way to the monastery, 19 June 1976, T. Nersisyan & Z. Kara-Akopyan (ERCB) [as O. crenata by T. Tsaturyan]; Noyemberyan distr., SE forest, 4 km of Noyemberyan to Jujevan, 16 June 1960, B. Bramyan (ERCB) [as O. flava by T. Tsaturyan]; Dilijan, beech-hornbeam forest, SE slope, 4 July 1948, R. Karapetyan (ERE) [as O. flava by I. Novopokrovskij]; Idjevan region, 10 km from Idjevan, in the forests, 25 June 1965, Gevorkyan (ERCB) [as O. crenata by T. Tsaturyan]; Idjevan distr., Revazlu vil. [Ditavan], hornbeam forest, 17 June 1964, Ja. Mulkidjanjan (ERCB) [as O. alba by T. Tsaturyan].

Figures

FIGURE 52. Orobanche laxissima. A. General habit. B–G. Inflorescences. Photos by Renata Piwowarczyk.

FIGURE 53. Orobanche laxissima. A. Plant. B. Flower, side view. C. Flower, front view. D. Leaf. E. Bract. F. Calyx. G. Open corolla and androecium. H. Anther. I. Gynoecium. J. Stigma. Illustration by Jolanta Urbanik.

FIGURE 55. Orobanche transcaucasica holotype. Azerbaijan, Shemackha Region (environs of the Sharadil village, in mixed forest (Carpineto-Quercetum), at ca. 800 m, 6 June 1941, I. Schchiponova (BAK 0-0000063).