A Taxonomic Revision of Two Species Complexes Belonging to the Haplotricha Subsection in the Genus Onosma (Boraginaceae): A Realistic Approach to Plant Diversity

Abstract

The taxonomy of O. dichroantha, O. nervosa, and their allied species is extremely controversial among authors. The delimitation of these species was extremely confusing, and closely related species were separated by weak and non-diagnostic morphological traits. A taxonomic revision of these taxa is presented here based on our fieldwork and a thorough study of herbaria specimens. The species O. dichroantha and O. sharifii are regarded as synonyms of O. setosa, and O. maculata is reduced to synonymy with O. nervosa. In addition, the typification of accepted names and relevant synonyms, detailed morphological descriptions and brief comments on the relationships between species are provided. Besides, it is accentuated that the introduction of any new species should be based on complete evidence to avoid systematic complexity. The results of this study play an important role in solving the problems of plant diversity and in the conservation of plant diversity.

1. Introduction

The genus Onosma Linnaeus (1762: 196) is one of the largest genera of the Boraginaceae tribe Lithospermeae, encompassing approximately 240 species [1] distributed mainly in the mountainous habitats of the Irano–Turanian region. The geographic distribution of the genus ranges from Mount Taibai in the southwest of Shaanxi Province, China (in the east) to the west of Souss–Massa–Daraâ in Morocco (in the west) and from Central Siberia and the Altai Mountains in Russia (in the north) to Doi Hua Mot WS in the north of Thailand (in the south) (see the occurrence data on the GBIF website: https://www.gbif.org/species/2925854) (accessed on 20 May 2020). Most Onosma species grow in sunny and xeric habitats, including rock and sandy soils and diverse geological formations including serpentine subgroup rocks [2,3,4,5]. The main diversity centers, as well the areas of endemism of Onosma, occur in Turkey and Iran [6,7,8,9,10,11,12,13,14,15,16]. The species in this genus share scorpioid cymes, tubular-campanulate or clavate corolla, calyx parted to or nearly to the base with linear or linear-lanceolate lobes, un-appendage, nectariferous throat glands, and erect achene. Onosma as a taxonomic complex group includes many complicated species [2,3,17,18,19,20]. Determining the boundaries of the species of this genus has created many problems because of the high rate of hybridization and several ploidy levels [18], as well as several morphological variations and large geographical distributions. The first taxonomic arrangements of Onosma were based on morphological characters, i.e., calyx characteristics and features of the leaf trichome [21,22,23]. The type of leaf indumentum is still an important diagnostic characteristic in this genus [24], but on its own it cannot solve the problems of the complex groups within this genus [2,20].

The genus Onosma is represented by 107 taxa in Turkey, 54 (50%) of which are endemic [25]. After Turkey, Iran is the second largest center of species diversity of this taxon in the world, and the Zagros Mountains, especially the Central Zagros, are home to many rare and local endemic species [11,16,19,26,27,28,29]. During the taxonomic revision of the genus in Iran, two complex groups were identified for which the determination of species boundaries was extremely confusing, and closely related species were separated by restricted morphological traits.

The first controversial species is the complex of O. dichroantha Boiss. In 1849, Edmond Boissier described a new species similar to O. setosa Ledeb. and named it O. dichroantha [30]. A few years later (1879), he cited this taxon as a variety of O. setosa [O. setosa Ledeb. var. dichroantha (Boiss.) Boiss.] [31]. Later researchers, including Popov (1953) [32], Riedl (1967) [23], and Khatamsaz (2002) [33], synonymized O. setosa Ledeb. var. dichroantha with O. dichroantha and accepted it as a separate taxon. Riedl (1967) described O. sharifii Riedl as a new endemic species for the flora of Iran [23]. This species also has morphological characters quite similar to those of O. dichroantha and O. setosa. Our field studies and the protologues of the species show that these three species, in addition to having similar taxonomic features, are found mostly in similar habitats in the highlands near the Caspian Sea. Therefore, a careful review to determine their taxonomic value is essential.

The second group of doubtfully distinct species is the complex of O. nervosa Riedl and O. maculata Ranjbar & Almasi. In 1962, Riedl named O. nervosa as a new species for Flora Iranica [34]. This species grows in Iran and Iraq. Recently, O. maculata has also been described as a new Iranian Onosma species very similar to O. nervosa [35]. Given that only tenuous characteristics separate these species from one another, more investigation to determine their actual circumscription is needed. Therefore, the present study is intended to provide an updated taxonomic revision of the mentioned complex groups to clarify the nomenclature status and taxonomic relationships among them

2. Materials and Methods

The present study is primarily based on the consultation of the relevant literature, field surveys, and examination of specimens from the following herbaria: HSBU, IRAN, TARI, and W, WU. In addition, high-resolution digital images of specimens were obtained from 22 other international herbaria including JE, MPU, B, BM, C, E, G, GH, HAL, K, LD, LINN, M, MA, MEL, MO, P, PRC, S, TU, US, UPS, and WAG; herbarium acronyms follow Thiers (2020) [36]. Extensive field collecting was conducted in different parts of Iran from 2009 to 2019. The collected specimens were kept at HSBU. The morphology of the specimens was also studied carefully in the present study.

3. Results and Discussion

3.1. O. dichroantha Complex Group

In the present study, we examined in detail more than 115 specimens of the O. dichroantha complex. Detailed morphological studies of specimens revealed that the main diagnostic characters of this complex group are broadly linear or oblanceolate basal leaves, pedicels elongated in fruit, setae with hispid tubercles, glabrous nectaries, shiny and strongly gibbous nutlets.

3.1.1. Taxonomic Treatment

Onosma setosa Ledeb. (1820: 70).

Lectotype:—RUSSIA. Astrachan, sine die, F. Blum, (designated by Popov 1953: 214) (LE); Neototype:—: neototype, designated here) LE [LE01042916, digital image!].

≡ O. dichroantha Boiss. (1849:107), O. setosa var. dichroantha (Boiss.) Boiss. (1879:181). Type:— TRANSCAUCASIA. Iberia prope Baku, C.A. Meyer s.n. (G); N. IRAN. in monte Demavend prope Ask, 1843, Kotschy 383, (syntype: K [K000958673, digital image!], BM [BM001014474, digital image!], BM [BM001050253, digital image!], W [W0030927, digital image!], W [W0030928, digital image!], LE [LE01071798, digital image!], LE [LE01071799, digital image!]), P [P04069538, P04069539, P04069540, digital images!], (lectotype: LE [LE01071799, digital image!]; isolectotype: LE [LE01071798, digital image!]). syn. nov.

=O. sharifii Riedl. (1967: 198). Type:—IRAN. Mazandaran: Hazar Jarib, Sharif 505 (holotype: W, 1966–0020231!]. syn. nov.

3.1.2. Emended Description

Biennial or perennial; Stems solitary or several, 15–70 cm high, erect or ascending, usually green or slightly reddish, sometimes bluish, with dense long spreading bristles, with branches terminated by inflorescences in the upper half, covered with short, rather dense, coarse down between long horizontal bristles; Indumentum cover with setae 1–4 mm long and tubercles, glabrous or pubescent, shorter hairs less than 0.5 mm long. Basal leaves elongate, broadly linear or oblanceolate, 100–250 × 4–15 mm, base attenuate, apex often obtuse; Cauline leaves sessile, oblanceolate or liner 25–100 × 5–10 mm; Inflorescence terminal, elongated after flowering; Pedicels short, to 7 mm in flower, elongated in fruit; Bracts lanceolate; Calyx 10–25 mm in flower, to 30 mm in fruit, outside with spreading white or yellow bristly hairs, divided nearly to base; lobes linear-lanceolate; Corolla yellow at first, becoming purplish or light brown, 25–40 mm long, tubular-campanulate, glabrous both sides or pubescent in curved teeth or sub glabrous inside, with small, triangular, curved teeth; Style 20–30 mm, exserted from corolla, Anthers connate at base, 8–10 mm, Annulus glabrous; Nutlets shiny, yellow-brown, 4–6 mm, strongly gibbous.

3.1.3. Taxonomic Notes

O. setosa was described as a new endemic species for the Caspic-caucasian region [37]. This species is characterized with the following description: Rosette leaves elongated, linear, lanceolate. Corolla yellow, spatulate, broadly tubular-campanulate. Setae tuberculate. Nectaries glabrous. Cauline leaves lanceolate, to ovate, acute-acuminate; Setae white, spreading bristly hairs. Inflorescence broadly paniculate to solitary, calyx floriferous and double in length. Stigma bilobed. Nutlets, shining, quadrate or triangular.

In 1849, Edmond Boissier described a new species with morphological traits closely similar to O. setosa and named it O. dichroantha. A close examination of the original descriptions of these two species showed that these two diagnostic traits of O. dichroantha are in the morphological range of the O. setosa species, and no significant morphological differences were observed between these two species (Figure 1 and Figure 2). Therefore, according to our observations of the herbaria specimens of these taxa, the investigation of the original descriptions, and reviews of syntypes, we propose that O. dichroantha be recognized as a new synonym of O. setosa. Furthermore, the original descriptions of O. setosa and O. sharifii are completely congruent, and these species share the same morphological traits. Our evaluations based on the original taxonomic description of O. sharifii as well as the diagnostic characteristics of the investigated populations of O. setosa suggest that this taxon must also be reduced to synonymy with O. setosa.

3.1.4. Neotypification of O. setosa

In the protologue, Ledebour mentioned the specimens from the Caspian habitats near the city Astrakhan of Russia as the original material of O. setosa [37]. The type material of O. setosa was said to be deposited in the Leningrad herbarium according to Flora USSR [32]; however, it was not found there, and no relevant information about it is available in the herbarium database (Petr Efimov, T. Lebedeva, LE staff, by e-mail, April 10 and 11, 2018, and Irina Illarionova by e-mail, 3 May 2018). Moreover, our search in the following herbaria yielded no results: C, B, BM, E, G, GH, HAL, JE, K, LD, LINN, M, MA, MEL, MO, MPU, MW, P, PRC, S, TU, UPS, US, WAG and WU. As there is no illustration or syntype of this taxon in the protologue, it is necessary to introduce a neotype. In our opinion, the best candidate for designating a neotype should be selected from the Ledebour collection and the location of the type. Six digital images of this species, thought to be type specimens, were sent to us by the Vascular Plants Herbarium of the Komarov Botanical Institute (LE) (Figure 3).

By carefully examining the information of the place and year of collection and the name of the collector, it was determined that only two specimens, those with barcodes LE 01042916 and LE 01042911, are in the Ledebour collection. The specimen with the barcode LE 01042911 was collected from Turcomania (area S of Georgia; wrong region) and thus is not a suitable candidate for neotype design. Finally, we conclude that the specimen with the barcode LE 01042916 collected from the Eastern Europe sector of the Caspian lowland desert can be designated as a neotype for O. setosa. We believe the protologue does not refer to a specimen only as the original material of this species; perhaps LE 01042916 is part of it and can be a candidate to select a neotype (ICN Art. 9.16-18). This sample is present in the LE herbarium and its location closely matches the location information of the original material mentioned by Ledebour.

• Phenology:—Flowering from mid-May to mid-July, fruiting from June to early August.
• Distribution: —Caucasus, Iran, Central Asia.
• Specimens examined: —IRAN. Azarbaijan: Ca. 25 Km SE. of Jolfa, Kiamaki protected area, Gheshlagh village, Kuh-e Gelenj, 2100–2700 m, 19 June 1988, M. Assadi & A. Shahsavari 65746 (TARI!); Mountains of SW. of Ahar, 2500 m, 22 June 1988, M. Assadi & A. Shahsavari 65936 (TARI!); Bostan Abad to Tabriz, 5 June 1962, P. Furse 12550 (W!); Ahar, Sarichaman, Vanatan, F. Termeh (IRAN!); Golestan: Golestan National Park, Tangerah, Ghorbangali, Sararbaghi, M. Ghorbani et al. 2017204 (HSBU!); Gorg: Golestan National Park: between Sharlegh & Tcheshmeh-ye Khan, B. Zehzad 2017202 (HSBU!); Gorgan, Park-e Meli, 11 Km Sulgerd, 1520 m, 16 July 1991, F. Matin & F. Termeh 18997 (IRAN!); Golestan National Park, 1750 m, 19 June 1974, P. Wendelbo & H. Foroughi 17903 (W!); Gorgan, 2400–2600 m, 26–27 July 1948, K. H. Rechinger 6835 (W!); Kuh-e Aghaman, 1100 m, 18 May 1975, M. Renz 05739 (W!); National Park of Golestan, Almeh, 1200 m, 5 June 1979, K. H. Rechinger 05733 (W!); National Park of Golestan, Almeh, 1500–1800 m, s.c. 13434 (W!), Almeh, 1850 m, 8 May 1972, H. Foroughi 3746 (TARI!); Park-e Golestan, Almeh, 1350–1700 m, 5 June 1987, V. Mozaffarian & Abouhamzeh 59051 (TARI!); Almeh, 1200–1300 m, 7 June 1975, F. Termeh 2759 (IRAN!); Almeh, 1630–1750 m, 18 July 1991, F. Matin & F. Termeh 18998 (IRAN!); Almeh, 1550–1850 m, 21 June 1993, F. Matin & F. Termeh 60088 (IRAN!) Khorassan: Hezar Masjed, 2000–2600 m, 8–9 July 1948, P. Allen 5652 (W!); Esfarayen, Kuh-e Shah Jahan, Saracheshmeh village, 1700 m, V. Mozaffarian 48407 (TARI!); Ca. 45 Km of N. of Shirvan, Golool-Sarani protected area, 1600–2300 m, 26 May 1984, M. Assadi & A. A. Maasoumi 50512 (TARI!); Between Ghouchan & Darreh-Gaz, Tandooreh National Park, Shekarab, 2300 m, 27 May 1984, M. Assadi & A. A. Maasoumi 50602 (TARI!); Esfarayen, N.slope Kuh-e Shah Jahan from Darparchin-e Bala village, 1700–2500 m, 7 June 1984, V. Mozaffarian 48444 (TARI!); 5 Km Mozduran to Sarakhs, 650 m, 26 April 1989, V. Mozaffarian 67617 (TARI!); Shahpasand to Shahrud, 1800–1950 m, 18 May 1978, P. Wendelbo & M. Assadi 29686 (TARI!); Ca. 30 km between Esfarayen to Bojnurd, 1800–2000 m, 29 June 1984, V. Mozaffarian 48722 (TARI!); Fariman, 1429 m, 16 May 2003, M. Assadi & M. Amirabadi 84534 (TARI!); Mountains of N. of Ghouchan, above the village Zubaran, 1950 m, 19 July 2003, M. Assadi & S. M. M. Hamdi 85632 (TARI!); Bojnurd, near Chamanbid, 21270 m, 9 May 1984, H. Foroughi 3744 (TARI!); Dargaz, 35 Km of Daroongar village, 13 June 1988, A.Vafaee 227 (TARI!); Kopet Dagh, 45 km NE. of Shirvan, Gulul Valley, 2300 m, 30 June 1973, R. Edmondson 1185 (TARI!); Golal Sarani Area, 2100–2300 m, 12–13 June 1975, 13432 (W!); Neyshabur, Akhlamad waterfall, 1600–1800 m, 30 May 1948, K. H. Rechinger & P. Allen 6838 (W!); Between Mashhad and Sarakhs, 1000 m, 25 May 1977, K. H. Rechinger 07776 (W!); 24 Km south of Bojnord to Esfarayen, 1700–1800 m, 15 June 1975, 13430 (W!); N. Shirvan, 2200 m, 12 June 1975, K. H. Rechinger 13431 (W!); Kopet Dagh, Northeast Shirvan, 2300 m, 30 June 1973, R. Edmondson 28885 (W!); Between Shahrud and Bojnourd, 800 m, 23 May 1977, K. H. Rechinger 08098 (W!); Shahpasand vers Bojnurd, Almeh, 10 June 1975, F. Termeh 2762 (IRAN); Esfarayen to Bojnurd, 25 Km Bojnurd, 16 June 1975, 1700 m, F. Termeh 2754 (IRAN!); Shirvan, Namanlu, Kuhhay Gulul, 2200–2500 m, 14 June 1975, F. Termeh 2760 (IRAN!); Fariman to Torbat-e Heydariyeh, 1200–1400 m, 25 June 2009, A.R. Mehrabian 2017200 (HSBU!); Mashhad south area, 1200 m, 13 June 2010, A. R. Mehrabian 2017203 (HSBU!); Quchan to Dargaz, 80 Km Dargaz, 14 July 2019, M. Arabameri 2017330 (HSBU!) Mazandaran: Inter Gach-i-sar et Chalus,0–3000 m, 18 May 1956, F. Schmid 5795 (W!); Chalus, 10 Km from Vissar on road to Marzanabad, 1250 m, 18 April 1978, V. Mozaffarian 27348 (TARI!); Siah-bisheh, 2500 m, M. Assadi 76689 (TARI!); Mazandaran, Haraz road to Abgarm, 2250 m, 23 June 1971, M. Assadi & V. Mozaffarian 33144 (TARI!); Tehran, Tunle Kandavan, 2220 m, 27 June 1973, K. Bazargan & GH. Amin 1428 (TARI!); Tehran, S. slope of Demavand Mout., 3300–3800 m, M. Khatamsaz et al. 04718 (TARI!); Chalus valley, below Siah Bisheh, 2000 m, 24 May 1974, P. Wendelbo & A. Shirdelpour 11694 (TARI!); Firoozkooh, Veresk Bridge, 1690 m, 12 May 1971, Gheissari 1348 (TARI!); Kelardasht, Rudbarak, 1980 m, 10 June 1973, R. Fotovat 10141 (TARI!); Kelardasht, Kalalur, 1200 m, 14 May 1971, H. Foroughi 1371 (TARI!); Firoozkooh, Veresk Bridge, Bazargan & Arazm, 1600 m, 10 June 1973, 1430 (TARI!); Siahbisheh, 2500 m, M. Assadi 76689 (TARI!); Firoozkooh, Veresk Bridge, 2000 m, 25 June 1974, P. Wendelbo & H. Foroughi 22163 (W!); Chalus road, 2000 m, 25 July 1964, K. H. Rechinger 16890 (W!); Alborz, between Chalous and Karaj, 2190 m, 24 June 1966, J. C. Archibald 17333 (W!); Mazandaran, Chalous, 2400 m, 9 June 1937, K. H. Rechinger 889 (W!); between Kandavan and Elika, Duna village, 2550 m, 23 June 1979, M. Assadi & V. Mozaffarian 32901 (TARI!); Alborz, Kandovan, 2700–3000 m,26 May 1937, K. H. Rechinger 888 (W!); Chalous to Pol-e Zangouleh, 2300 m, 21 June 1974, K. H. Rechinger 13565 (W!); Gachsar, Pol-e Zangouleh, 1500 m, 29 June 1997, S. Shirzadian et al. 60061 (IRAN!); Noor, 1000 m, 22 June 2017, A. R. Mehrabian 2017201 (HSBU!); Yoosh & Baladeh 3000 m, 1 July 2013, A. R. Mehrabian 2017204 (HSBU!); 3 km Siyah Bisheh, 2189 m, 27 July 2017, A. Neemati 2017205 (HSBU!); Noor, Baladeh, 2 Km Kamarbon village, 2409 m, 27 July 2017, A. Neemati 2017206 (HSBU!); Veresk bridge, 2400 m, 14 July 2016, A. R. Mehrabian & F. Khajoei Nasab 2017301 (HSBU!); the road of Chalus to Kamarbon village, 2417 m, 27 July 2017, A. Neemati 2017207 (HSBU!); the road of Chalus to Kamarbon village, 2497 m, 27 July 2017, A. Neemati 2017208 (HSBU!); the road of Chalus, 45 Km Baladeh, 2705 m, 27 July 2017, A. Neemati 2017209 (HSBU!); The road of Baladeh after Kamarbon village, 2835 m, 27 July 2017, A. Neemati 2017210 (HSBU!); 30 Km Baladeh in the Kamarbon road, 2837 m, 27 July 2017, A. Neemati 2017211 (HSBU!); The road of Baladeh, after Kamarbon village, 2974 m, 27 July 2017, A. Neemati 2017212 (HSBU!); The road of Baladeh, after Kamarbon village, 3059 m, 27 July 2017, A. Neemati 2017213 (HSBU!); Noor, Baladeh, Nesen village, 2589 m, 28 July 2017, A. Neemati 2017214 (HSBU!); South of Damavand, toward Meiandeh, 1658 m, 28 July 2017, A. Neemati 2017215 (HSBU!); 1 Km Deladasht from Miyandeh, 1918 m, 28 July 2017, A. Neemati 2017216 (HSBU!); Amol, Larijan, Nandal village, 2183 m, 28 July 2017, A. Neemati 2017217 (HSBU!); 1 km of Baladeh to Royan village, 2524 m, 28 July 2017, A. Neemati 2017218 (HSBU!); 1 km of Baladeh to Royan village, 2722 m, 28 July 2017, A. Neemati 2017219 (HSBU!); Baladeh to Royan village, 2950 m, 28 July 2017, A. Neemati 2017220 (HSBU!); Kojur District, Kodir village, 1503 m, 28 July 2017, A. Neemati 2017221 (HSBU!); Kelardasht, Rudbarak, 1709 m, 14 July 2018, A. Neemati 2017222 (HSBU!); Kelardasht, Vandarbon, 1907 m, 14 July 2018, A. Neemati 2017223 (HSBU!); Polur to Rineh, 2334 m, 14 July 2018, A. Neemati 2017224 (HSBU!); Firuzkuh, Veresk, 2334 m, 14 July 2018, A. Neemati 2017225 (HSBU!); Firuzkuh road, Pol-e Sefid, 1257 m, 15 July 2018, A. Neemati 2017226 (HSBU); Firuzkuh road, Gadok-pass, 2111 m, 15 July 2018, A. Neemati 2017227 (HSBU!) Semnan: Naudeh et Shahrud, 1000–2000 m, 15 June 1956, F. Schmid 6117 (W!); 57 Km of SE. Shahpasand, 1250 m, 10 May 1966, H. Pabot 25618 (TARI!); Between Shahpasand and Shahrud, Khoshyeylagh, 1600–1800 m, 18 May 1978, P. Wendelbo & M. Assadi 29626 (TARI!); Shahrud, Khosh yeylagh, 2000 m, 26 June 1972, M. Riazi 3718 (TARI!); Shahrud, Khoshyeylagh, 27 June 1952, A. Zargani 2761 (IRAN!); 45–52 Km Shahmirzad, Fulad mahalleh, 2200–2300 m, 9 July 1974, M. Renz & A. Zargani 2753 (IRAN), Semnan, Parvar protected area, 2200 m, 30 May 1975, K. H. Rechinger 13433 (W!), Shahrud, Khosh yeylagh, 2030 m, H. Foroughi 10414 (TARI!); 69 Km Shahrud from Azadshahr, Gardane-Khosh yeylagh, 2000 m, 3 August 1982, M. Assadi & V. Mozaffarian 40969 (TARI!); Shahrud, Kuh-e Ghatry, 2310 m, 8 June 1984, H. Foroughi 8986 (TARI!); ca. 50 Km N of Semnan, between Sheli to Hikuh villages, 2400 m, 28 July 1971, M. Assadi & V. Mozaffarian 40621 (TARI!); AFGHANISTAN. Nozi, 9000 ft, 21 June 1937, W. N. Koelz 11987 (W!), Faizabad, 1100–1900 m, 11 July 1948, L. Edelberg 1397 (W!), Badghiz, Kush Asia, Khaleqdad, 900 m, May 1969, Janata 33 (W!), Kouh-Tchehel Dokhteran, 1 July 1959, L. Edelberg 7229 (W!), Khash-Dt, 8000 ft, 8 August 1937, W. N. Koelz 12915 (W!), Polat, 9000 ft,10 September 1939, W. N. Koelz 13949 (W!), Jaji, inter Ahmad Khel et Ali Khel, 2200 m, 2400 m, 9 July 1965, 32195 (W!), Khost, Jugi Sata Kandao inter Gardez, 2200–2800 m, 8 July 1965, 32145 (W!), Paghman, 7000 ft, 12 May 1937, W. N. Koelz 11389 (W!), Mazar-I Sharif, Balkh supra Aq Kupruk, 700–800 m, 6–7 June 1962, 16309 (W!) Armenia. Syunik province, c.4 Km NW of Sisian, 1785 m, 4 July 2003, 030752 (W!), Vayots Dzor province, area SSE of Vayk, 2010 m, 15 June 2009, Tamanian 03487 (W!) Georgia. Dedoplistskaro District, Iori plateau, Environs of village Kasristskali, on road from village to Vashlovani reserve, 555 m, 14 May 2006, N. Lachashvili 340 (W!), Caucasus. distr. Razdan, clivi montis Ketandag in vicinitate pagi Charencavan, 1700–2100 m, 7 July 1975, Vasak 02228 (W!) TURKMENISTAN. Regio transcaspica Aschabad, in glareosis montium supra pagum Nephton, 4 May 1990, s.c. 212 (W!).

3.2. O. nervosa Complex Group

A total of 13 specimens of the complex group of O. nervosa were investigated. The main diagnostic characters included large (up to 25 cm) and lanceolate rosette leaves, prominent reticulate veins, glabrous nectary, setae with glabrous tubercles as well as very short and sparse rays and golden yellow corolla.

3.2.1. Taxonomic Treatment

Onosma nervosa Riedl (1962: 234). Type:—IRAQ. Kajan Mountain, nr. Penjwin, 1590 m, 21 June 1957, A. Rawi in Nat. Herb. Iraq 22705 (holotype: K [K000852615 digital image!]).

= O. maculata Ranjbar & Almasi (2015: 522–525). Type:—IRAN. Lorestan, Khorramabad to Sefid Dasht, Dareh Ashkaft, 1300 m a.s.l., 28 May 2012, Ranjbar & Almasi 30194 (holotype: BASU [digital image!]). syn. nov.

Notes:—O. maculata shows great similarity to O. nervosa having large rosette lanceolate leaves, reticulate veins, and middle and upper stem leaves oblong to liner-lanceolate; both of them also include 2 terminal or 1–2 lateral cymes, elongated fruit, and lanceolate bracts. In addition, they are similar in calyx and corolla (size, shape of lobes and color) and glabrous nectaries. The two mentioned taxa are also similar in the lengths of leaf, calyx, bract, pedicel, corolla, and anther. However, some weak characters (e.g., tubercle color, spots of stems and peduncle, hair density variations in different parts) cannot be the main basis for the differentiation and separation of different species in the genus Onosma and other genera of Boraginaceae [20] (Figure 4 and Figure 5).

These characteristics have been frequently observed in different populations of both species in various herbaria (Figure 6). Accordingly, we suggest that O. maculata is synonymous with O. nervosa.

• Phenology:—Flowering from mid-June to mid-July, fruiting from June to early August.
• Distribution:—Iran, Iraq.
• Specimens examined—IRAN:—Lorestan: Hamedan: Nahavand, Gamasiab, 2119 m, 21 July 2017, M. J. Nikjouan 20178602 (HSBU!) Kermanshah: Malavi to Eslamabad, 1200 m, 7 June 2007, V. Mozaffarian 64384 (TARI!), Ravansar, Shaho, 1801 m, 20 June 2017, M. J. Nikjouan 20178603 (HSBU!) Kurdestan: Sannandaj to Divandareh, 9 June 2016, M. Arabameri 20169851 (HSBU!); 15 Km Marivan to Sannandaj, 1000–1850 m, 8 July 1995, V. Mozaffarian 74656 (TARI!); 11 Km Kamyaran to Kermanshah,1800–2000 m, 15 June 1987, M. Assadi 60660 (TARI!); Kamyaran to Sonqor, 1970 m, 3 June 2001, B. Hamzei & Y. Asri 87747 (TARI!); Kamyaran to Sonqor, Tang-Gharal, 1700 m, 3 June 2001, B. Hamzei & Y. Asri 87744 (TARI!); Isfahan, Kuh-e Venizan, 2500 m, 8 July 1996, V. Mozaffarian 77244 (TARI!); Baneh, 2200 m, K. H. Rechinger, 05718 (W!); Sanandaj, Saral region, close to Ghuluze village, 1987 m, 7 June 2007, V. Mozaffarian 93244 (TARI!) Lorestan: Khorramabad to Borujerd, Zagheh, 1944 m, 15 June 2017, M. J. Nikjouan 20178579 (HSBU!); Borujerd to Khorramabad, 2174 m, 15 June 2017, M. J. Nikjouan 20178601 (HSBU!); Borujerd, Kuh-e Garin, 2103 m, 9 July 2017, M. J. Nikjouan 20178601 (HSBU!); Khorramabad to Sefid Dasht, Dareh Ashkaft, 1320 m, 15 June 2017, M. J. Nikjouan 20178605 (HSBU!); 25 Km Khorramabad to Sefid Dasht, 1600 m, 30 May 2005, M. Assadi & I. Mehregan 88935 (TARI!).

3.2.2. Emended Description

Perennial, 40–50 cm high, long woody rhizome. Stems several, erect to ascending, distinctly spotted with dark purplish to black tubercles. Setae appressed, glabrous tubercles, with semi-dense white to yellow. Rosette leaves lanceolate, 120–230 × 20–30 mm, reticulate venation, attenuate at the base, acute at the apex to a long petiole up to 60 mm. Middle and upper cauline leaves liner-lanceolate, sessile, 40–120 × 10–35 mm. Inflorescence paniculate, 10–15 cm, white pubescent, elongated in fruit. Pedicel 3–15 mm. Bracts lanceolate, 3–20 mm, Calyx divided to base, 10–12 mm, elongated up to 16 mm in fruit; lobes lanceolate, 1–2 mm wide, white-yellow bristles outside. Corolla, campanulate or clavate-campanulate, 12–22 mm, golden yellow; lobes triangular, obtuse, 1.5 × 2–3 mm, densely pubescent outside. Annullus glabrous. Anthers connate at base, 6–10 mm long. Style filiform, little out of corolla; stigma bilobed. Nutlets 7–8 mm, ovoid, keeled above, glabrous, light brown.

4. Conclusions

The species O. dichroantha and O. sharifii are regarded as synonyms of O. setosa, and O. maculata is reduced to synonymy with O. nervosa. In addition, the typification of accepted names and relevant synonyms, detailed morphological descriptions and brief comments on the relationships of species are provided. Moreover, we emphasize that the introduction of any new species should be based on complete evidence to avoid systematic complexity. The results of this study play an important role in solving the problems of plant diversity and in the conservation of plant diversity. The accurate delimitation and identification of species is the first step to determining priorities for conservation. Species are one of the main conservation units, and identifying accurate scientific names of them is therefore crucial to gathering reliable information in conservation biology.