Arenaria bulica Stapf ex F. N. Williams (1898: 374)

Type:— IRAN. Prov. Fars, Mt. Kuh-Bul [Bol], 1885, Stapf s.n. (holotype K000723749!) (Fig. 1).

= Arenaria minutissima Rechinger filius & Esfandiari (1951: 342), syn. nov.

Type:— IRAN. Prov. Fars: Mt. Kuh Dinar (Dena), Sichani Pass, 1 Aug 1949, Behboudi 1306 E (holotype W 16719!, isotype IRAN 5025!) (Fig. 2).

= Arenaria semiromica Fadaie (2013: 33), syn. nov.

Type:— IRAN. Prov. Esfahan, East of Semirom, Aineh-Ghabri Mt., 3000-3700 m, 9 Aug 1978, Assadi & Mozaffarian 31703 (holotype TARI!) (Fig. 3).

Ememnded description (Figs. 4–6):—Rough-pubescent cushion to rather mat perennial herbs, 3–8(–15) cm high. Stems bearing flowers numerous, filiform, short, decumbent-ascending, 15–30(–50) mm long. Leaves minute, lower obovate (barely ovate), 1–3 × 0.5–1.8 mm, upper spathulate to linear-oblanceolate, 2–5(–7) × 1–2(–3) mm, acute, tapering towards the base, barely petiolate, with a rough margin, upper ± glandular. Inflorescences terminal, leafy, 1–2- flowered cymes in distal leaf axils. Bracts lanceolate to narrow lanceolate with narrow membranous margin, acute to acuminate, glandular-hairy, 1.5–2.5(–3.0) × 0.3–1.3 mm. Pedicels equal to one and a half times the sepals, glandular-hairy. Sepals 3–5 × 1.2–1.6 mm long, broad lanceolate to ovate, shortly acuminate, herbaceous with scarious margin, indistinctly uninerved, glandular-hairy. Petals ovate-lanceolate, apex ± rounded, base scarcely clawed, 5–7(–8) × 1.8– 2. 6 mm. Styles 3, filiform. Stamens 10. Capsules tightly enclosed by calyx, ovoid to suborbicular, shorter than sepals, 2.0–2.7 × 1.5–2.0 mm, opening by 6 recurved teeth. Seeds shiny black, sub-reniform-orbicular, 0.8–1.0 × 0.7–0.8 mm. Seed surface regularly polygonal to elongate cells with irregular straight margins and convex periclinal walls.

Notes: —Since 1885, when few individuals from Bol Mt. of Arenaria bulica was collected by Stapf (Fig. 1), no specimen has been collected from type locality. Therefore, our collections from two different slopes of Bol Mt. are the second and third ones after ca. 139 years (Figs. 4–5). Type specimens of A. minutissima are from Dinar Mountain (Fig. 2) (Rechinger 1951) and in Rechinger’s Flora Iranica two specimens are mentioned, one being the type specimen and another one from Lalezar Mountain in Kerman (Kuh-e Lalezar, 3800 m, Starmüller 138) (Rechinger 1988). Rechinger (1988) has also mentioned another miserable voucher of Kerman, Lalezar Mt. which has been collected by Gabriel (no. 232) and identified as A. bulica (Rechinger 1988). In fact, two different collections of Gabriel and Starmüller from the same locality was considered by Rechinger as different species. Later on, another chasmophytic alpine species of the genus, A. semiromica, has described from Esfahan, Semirom, Aineh-Ghabri Mt. by Fadaie (2013). Recently, all Iranian Arenaria species has been revised by Fadaie (2023) who traced a duplicate of type specimen of A. semiromica as A. minutissima but with different number (TARI 31691).

In Flora Iranica and Flora of Iran, Arenaria bulica and A. minutissima are distinguished from each other by characters such as size and shape of leaves (3.0– 4.5 mm long, linear-lanceolate in A. bulica vs. 1–3 mm long, ovate-lanceolate in A. minutissima) and sepals (3.5 mm long, lanceolate vs. 4 mm long, ovate) (see Rechinger 1988, Fadaie 2023). Fadaie (2023) distinguish A. bulica and A. minutissima from A. semiromica by only the height of plant (up to 4 cm vs. up to 10–15 cm in A. semiromica) and A. bulica and A. minutissima was distinct by only leaves shape (lanceolate-linear vs oblanceolate to obovate), however the author has never collected and studied specimen from Bol Mountain despite her attempts.

After close examination of whole existing herbarium specimens of all three above mentioned species, as well as the newly collected specimens from Bol Mt., we found that Arenaria bulica is a species with high morphological plasticity as same as some other chasmophytic alpine species [e.g., Crepis demavendi Bornmüller (1907: 435), Dielsiocharis kotschyi (Boissier 1846a: 14) O.E. Schulz (1924: 184), Euphorbia aucheri Boissier (1846b: 94)]. Characters which have already separated these three species such as, size and shape of leaves and sepals, height of plant are overlapped in the studied specimens and are being subject of considerable variation. These characters have a low taxonomic value. Therefore, A. minutissima and A. semiromica fall within the morphological variability of the polymorphic A. bulica.

Seed macro and micro-morphology in some groups of Caryophyllaceae is valuable and efficient in delimitation of closely related taxa. (e.g. Amini et al. 2011; Mahdavi et al. 2012, Nejad Falatoury et al. 2015, 2016b, c, Arabi et al. 2017, Hoseini et al. 2017). In a rather comprehensive study, seeds of 64 taxa representing eight genera of the tribe Alsineae with special focus on the “ Arenaria complex” were analyzed, including 37 taxa of Arenaria and 15 species of Eremogone. Seeds colour in most studied Arenaria s.l. species are black and dull however; seed shape and size vary highly (Sadeghian et al. 2014). Here, we examined seed macro and micro-morphology of two different populations of A. bulica including, type specimen of A. semiromica and newly collected specimen of A. bulica from type location to evaluate and compare to each other. Among existing herbarium specimens with A. minutissima labels, no mature seed found for photo microscopy. In both populations, seeds macro and micro-morphology were similar as indicated in description part (Fig. 6F–I). This species has shiny black seeds whereas, most studied species by Sadeghian et al. (2014) are dull black. The testa cells are polygonal with colliculate-simple sculpturing and straight margins. Anticlinal walls of testa cells are deep with convex outer periclinal walls which are common characters in seeds studied species of Arenaria (Sadeghian et al. 2014) (Fig. 6). Seed macro and micro-morphology of A. bulica is the first survey as representative of Sect. Parviflorae McNeill (1988: 9) and no sample has been considered in previous seed micromorphology studies.

Ecology and conservation status: — Arenaria bulica has been collected by a few botanists from the alpine regions of central to southern Zagros on rocks and boulders (Fig. 7) at elevation 2900–3900 m. Remaining last year dried leaves, compact form, densely branched body, low growth form rates, and lack of developed soils in its habitat all together are features of one of the usual and well-known growth forms, cushion life, in the cold and dry Irano-Turanian alpines (Boucher et al. 2016). This kind of growth form, especially in the thornless type, is vulnerable to the harsh and unpleasant environmental conditions as well as other disturbance such as grazing. Based on conservation analysis, criterion B including extent of occurrence (EOO = 48970 km 2) and area of occupancy (AOO = 15000 km 2) it is assessed as LC (least concern), but according to criterion C, including number of mature individuals with less than 50 [C2(a)i] as well as few numbers of individuals in the field (only two small populations and 2–4 individuals for each during three years excursion in Bol Mt.), delicate and fragile habit, few number of localities (less than 6), exposed to the over-grazing and habitat as well as IUCN categories, the endemic chasmophytic alpine species (Fig. 5) is assessed as Critically Endangered (CR) (IUCN 2023). In the case of the herbarium specimen which has been collected from Lorestan province Runemark & Lazari 26477 (TARI), it is insufficient and immature specimen and its location in central Zagros is also far from the other ones occur in S Zagros. More materials need for final decision whether it would be confirmed as A. bulica or is another chasmophytic species.

Additional specimens studied:— IRAN. Prov. Chaharmahal va Bakhtiari, South of Sibak, North slope of Kallar mountain, 2800 m, 2 June 2007, Fadaie, Nasiri and Shahrokhi 1063 (TARI); Kuh-e Kallar from Sibak village, 2835 m, 31˚ 51′ 29″ N, 50˚ 56′ 22″ E, 4 July 2008, Mozaffarian 96810 (TARI); North slope of Kuh-e Kallar, South of Sibak, 2550-3200 m, 4 July 1986, Mozaffarian 57400 (TARI); South of Sibak, North slope of Kallar mountain, 3400 m, Fadaie, Nasiri & Shahrokhi 1067 (TARI); Sabzkuh, 2400-3190 m, 30 June 1986, Mozaffarian 57295 (TARI). Prov. Esfahan: East of Semirom, Kuh-e Aineh-Ghabri, 3000-3700 m, 9 Aug 1978, Assadi & Mozaffarian 31691 (TARI). Prov. Fars, Eghlid, Tang-e Asari, Bol Mt., 3700-3950 m, 30˚ 46′ 38″ N, 52˚ 45′ 02″ E, 27 July 2022, Pahlevani & Ghamghami 78123 (IRAN); South of Eghlid, Sugar factory road, Winter valley (Darreh Zemestani), Bol Mt., 3610 m, 30˚ 47′ 08″ N, 52˚ 44′ 40″ E, 14 Aug 2023, Pahlevani 78477 (IRAN); Kuh-e Dena, Gardaneh-e Bijan, 3000-3600 m, 2 Aug 1978, Assadi and Mozaffarian 31196 (TARI). Prov. Kerman, Kuh-e Lalezar, 3800 m., Starmuehlner, 138 (W 0209381); Kuh-e Lalezar, 1928, Gabriel 237 (W 0209380). Prov. Lorestan, Ghali kuh, E of the pass on road Aligudarz-Shoulabad, 3500 m, 1 July 1977, Runemark & Lazari 26477 (TARI).