Campanula oreodoxa Arjmandi & Memariani, 2021

Arjmandi, Ali Asghar, Ejtehadi, Hamid, Memariani, Farshid, Joharchi, Mohammad Reza & Mesdaghi, Mansour, 2021, Campanula oreodoxa (Campanulaceae), a new critically endangered species from the Aladagh Mountains, NE Iran, Phytotaxa 521 (3), pp. 193-202 : 194-199

Campanula oreodoxa Arjmandi & Memariani , sp. nov. ( Fig. 1–2 )

Type:— IRAN. North Khorassan: W Bojnord, Aladagh Mountains, Darkesh & Haver area , in alpine communities, 2385 m, 3 July 2018 (in flower), Memariani & Arjmandi 46390 (holotype FUMH!) .

Perennial, densely retrorse-strigose, ascending to decumbent, up to 10 cm high. Rootstocks woody, shortly branched. Stems herbaceous, leafy, up to 7 cm long, covered by leaf remains at the base, with numerous ascending branches, ending in usually 1(–3)-flowered racemes. Basal leaves in rosettes, densely retrorse-strigose, 20–30 (33) × 1–2 mm, sessile; cauline leaves ± similar to the basal leaves but smaller, 10–18 × 1–1.5 mm, sessile, entire, acute. Flowers subsessile, erect to suberect, terminal, rarely axillary, densely retrorse-strigose outside, long-hairy inside. Calyx without appendages, 4–5 mm long; calyx lobes 2–2.5 mm long and 1 mm broad, triangular, acute; calyx tube 2–3 mm long. Corolla campanulate-rotate, blue to purple, 6–9 mm long, divided about ¾; tube 1.5–2 mm long; lobes 5–7 mm long, retrorse, lanceolate, acute, long-hairy beneath. Stamens 4–6 mm; filaments white to yellow, dilated at base, 2–2.5 mm long, densely hairy at the base; anthers yellow, 2–3 mm long. Style slightly exserted from the corolla, 7–10 mm long. Capsule triangular, 4–6 × 3–5 mm, dehiscence with three pores at the base. Seeds ellipsoid to oblong, 0.7 mm long, shiny brown.

Phenology:—Flowering in late June to mid-July. Fruiting is completed from late July to mid-August.

Additional specimens examined (paratypes):— IRAN. North Khorassan: W Bojnord, Aladagh Mountains, Darkesh & Haver area , Barfandil summit, in alpine communities, 2385 m, 24 July 2018 (in fruit), Memariani & Arjmandi 46404 ( FUMH!) .

Etymology:—The specific epithet “ oreodoxa ” means “glory of the mountain” and refers to the high mountain habitat of the new species.

Taxonomic relationships:— Campanula oreodoxa belongs to C. subgen. Campanula sect. Oreocodon (Fedorov) Oganesian (1995: 293) [= C. sect. Saxicolae (Boiss.) Charadze ]. The species of C. sect. Oreocodon are mainly perennial, with pauciflorous stems, and without appendages between calyx lobes ( Rechinger & Schimann-Czeika 1965, Mansion et al. 2012). They resemble mostly the species of C. sect. Rupestres (Boiss.) Charadze by their lifeform, occurrence in crevices of rocks, and dehiscence of capsules with three middle or basal pores ( Fig. 2 ); however, calyces are appendiculate in C. sect. Rupestres . Campanula sect. Oreocodon is represented by 11 species in Iran, of which 9 species are endemic to the country. Campanula oreodoxa seems to be related to C. hystricula Pau in Pau & Vicioso (1918: 37), an endemic species to the central Zagros Mountains, but differs from the latter by its shorter stems (up to 10 cm), shorter corolla tube (1.5–2 mm), longer corolla lobes (5–7 mm), and the style position which is slightly exserted. In a revision of Pau’s types of plants, Rechinger (1990) accepted C. hystricula and completed its original description. Campanula oreodoxa differs from C. lourica Boissier (1849: 70) , endemic to Alborz and Khorassan – Kopet-Dagh Mountains, by the shape and size of its leaves and corolla ( Table 1). The molecular data is needed to realize the relationships and phylogenetic position of the new species within C. sect. Oreocodon.

Seed coat micromorphology:—Seeds in C. oreodoxa are fusiform to oblong, 1.60–1.86 mm long and 0.56–0.86 mm wide. The testa sculpture is striate with elongate cells and a narrow lumen ( Fig. 3 ). This type of seed coat belongs to Type I of testa in Campanulaceae which is generally characterized by a striate, interrupted striate, or faintly striate testa; however, the striate-reticulate pattern is common in Type II ( Akcin 2009, Alçitepe 2010). The seed coat of C. oreodoxa differs from that of the closely related C. lourica by its striate surface pattern with anticlinal walls extremely or relatively thick and rod-like in surface view (Subtype Ia), not smooth with an interrupted striate or faintly striate surface (Subtype Ib) ( Saeidi-Mehrvarz & Kashi 2015).

Pollen micromorphology:—Pollen grains of Campanula oreodoxa are radially symmetrical, oblate-spheroidal to spheroidal, or rarely prolate-spheroidal in shape ( Fig. 4 ). The polar axis is (19–) 21.21 ± 1.24 (–23.55) µm and the equatorial axis is (22–) 23.61 ± 1.06 (–25.17) µm with the shape index (P/E) of 0.90. The pollen grains are mainly triporate, rarely up to penta-porate. Previous studies have revealed that species of C. sect. Oreocodon, with pollen grains rather smaller than in the species of other sections, have most frequently three pores ( Khansari et al. 2012). In Table 2, the main pollen morphological features of C. oreodoxa are summarized and compared with the other chasmophytic species of Campanula in Khorassan –Kopet-Dagh Mountains. Pollen grains of C. oreodoxa can be distinguished by their smaller size and P/E ratio. The endemic species C. khorasanica (Rech.f. & Aellen) Rechinger in Rechinger & Schimann-Czeika (1965: 17) (sect. Rupestres ) differs from C. oreodoxa and C. lourica (sect. Oreocodon) by its rather larger pollen grains, and shorter and denser echinae on pollen surface.

Distribution and habitat:— Campanula oreodoxa is a local endemic restricted to the sub-alpine zone of western Aladagh mountain ranges, in Khorassan –Kopet-Dagh floristic province of the Irano-Turanian region ( Fig. 5A–B ). The new species occurs only in crevices of dolomite rocks at the summit of Barfandil Mount, at elevations of 2300–2400 m a.s.l. The habitat is mainly dominated by Cousinia edmondsonii Rechinger (1972: 321) , hitherto known only from Ghorkhod summit in the northwest of the study area ( Memariani et al. 2016c). The species associated with C. oreodoxa are listed in Table 3 based on three phytosociological relevés in the type locality.

Conservation status:—Based on the current data, the new species is restricted to a small area of 1.1 ha (EOO= 0.011km 2, AOO= 0.001km 2) with ca. 25 individuals ( Fig. 5C ). Following the IUCN Red List criteria, C. oreodoxa is evaluated as critically endangered (CR; B1+B2ab(iii) +C2a(i)). A very small extent of occurrence, area of occupancy and population size, as well as the global warming and grazing effects in southern slopes of the area, near the Barfandil summit, may bring the new species under extremely high risk of extinction. Moreover, the area has a high conservation value due to the presence of six threatened species endemic to Khorassan –Kopet-Dagh (30% endemism rate), as well as some sub-endemic or range-restricted plants ( Table 3).

Figures

FIGURE 1. Holotype of Campanula oreodoxa (46390 FUMH).

FIGURE 2. Campanula oreodoxa in its natural habitat. A. habitats dominated by Cousina edmondsonii and other cushion plants; B. plant in the flowering stage; C–D. close-up view of the flowers, E. plant in the fruiting stage with Cousina edmondsonii in background; F. the fruiting stage showing the dehiscence of the capsule by basal pores.

FIGURE 3. Scanning electron micrographs of Campanula oreodoxa seeds and details of testa sculpture.

FIGURE 4. Scanning electron micrographs of Campanula oreodoxa pollen grains.

FIGURE 5. A. Geographical position of the study area in northeastern Iran. B. Distribution map of the Campanula oreodoxa in the western Aladagh Mountains. C. Location of the populations of C. oreodoxa and the estimation of EOO and AOO in geoCAT based on IUCN Red List criteria.