Iberis saxatilis subsp. magnesiana Oskay, 2017

Oskay, Dilek, 2017, A new subspecies of Iberis saxatilis (Brassicaceae) from Turkey, Phytotaxa 306 (2), pp. 153-158 : 154-155

Iberis saxatilis subsp. magnesiana Oskay subsp. nov. ( Fig. 1 , 2 )

Type:— TURKEY. B 1 Soma district, Manisa province, Kocasivri Hill, 850 m, April 2009, (holotype EGE 42417, isotypes EGE, CBÜDepartment of Biology)

Small, evergreen, procumbent, diffuse subshrub with straight terminal flowering branches. Indumentum retrorsely setulose, variously dense, with hairiness increasing from the lower part to the top. Flowering stems 1.5–8 cm long, branched at base, ascending to erect. Leaves 3–12 × 1–2 mm, semi-cylindrical on sterile shoots and below on flowering stems; flat and involute on upper parts of flowering stems, sessile, entire, linear, acute, mucronulate, setulose on both surfaces. Inflorescence 8–15 × 9–15 mm, corymbose in flower, shortly elongating in fruit. Sepals 2.2–4 mm, concave, purplish, setulose, white membranous-margined, erect. Petals 4.5–7.5 mm (inner 4.5–6 mm, outer 6.5–7.5 mm), white to purplish-white, gradually narrowed into a short claw. Style 0.8–1.2 mm. Fruiting pedicels 5–6 mm. Fruits 6–9 × 4–6 mm, greenish to purplish, ovate to suborbicular, rounded at base, apex with 2 triangular lobes. Seed 2, brownish. Flowering and fruiting in March–June.

Etymology: The name of the species comes from Magnesia which is the ancient name of the province of Manisa.

Suggested conservational status: It is known from only the type locality until now. The total distribution area of the subspecies is approximately 1 km 2 and population density seems to be quite low. There are constructions of fire lookout tower and radio station buildings in its distribution area. Clearly, these buildings caused fragmentation and narrowing the distribution area. Besides, grazing pressure is rather high in this area. Having the above threats in mind, the new subspecies has been proposed as ‘Critically Endangered’ CR B2ab (ii, iii) according to the IUCN Red List criteria ( IUCN 2001).

Distribution and Ecology: Iberis saxatilis subsp. magnesiana was collected only from the type locality in West Anatolia. Field observations showed that Iberis saxatilis subsp. magnesiana has a local distribution in the upper part of the tree line at Kocasivri Hill. Soils of distribution area are slightly alkaline and generally have a calcareous structure ( Oskay & Altan 2015). Climate type is semi-arid upper Mediterranean and the winter period is rather cool. Iberis saxatilis subsp. magnesiana is an element belonging to the Mediterranean floristic region.

The new subspecies occurs together with such characteristic mountain steppe plants, often wind-resistant and cushionforming as Dianthus erinaceus Boiss. subsp. erinaceus Boiss. , Astragalus hirsutus Vahl , Acantholimon ulicinum (Willd. ex Schultes) Boiss. subsp. ulicinum (Willd. ex Schultes) Boiss. , Onosma tauricum Pallas ex Willd. var. tauricum and Erodium somanum H. Peşmen. Other common species are Asyneuma virgatum (Labill.) Bornm. subsp. cichoriiforme (Boiss.) Damboldt , Asyneuma limonifolium (L.) Janchen subsp. limonifolium , Chamaecytisus eriocarpus (Boiss.) Rothm. , Aubrieta deltoidea (L.) DC., Draba bruniifolia Stev. subsp. bruniifolia ( Oskay & Altan 2015) .

Paratypes: TURKEY. B1 Soma district, Manisa province, Kocasivri Hill, 850 m, April 2009, D. Oskay (1134) (EGE), Soma district, Manisa province, Kocasivri Hill, 850 m, May 2011, D. Oskay (1376) (EGE), (CBÜ-Department of Biology).

Taxonomic relationships: Iberis saxatilis subsp. magnesiana is separated from all other Iberis species quite easily except I. saxatilis subsp. saxatilis . It can be easily distinguished from I. saxatilis subsp. s axatilis by its stem indumentum which is retrorsely setulose in Iberis saxatilis subsp. magnesiana (most dense at the top) while in I. saxatilis subsp. saxatilis stems are glabrous. Besides the new subspecies differs from I. saxatilis subsp. saxatilis in leaves densely setulose on both surfaces (not glabrous on both surfaces only ciliate on margins when young, soon glabrous), sepals 2.2–4 mm, purplish, setulose (not 1.5–2.5 mm, green to purplish, glabrous), petals inner 4.5–6 mm, outer 6.5–7.5 mm (not inner 3.5–4.5 mm, outer 5–6.5 mm), fruit greenish to purplish, ovate to suborbicular, rounded at base, apically with 2 rounded lobes (not broadly winged from the base, with rounded lobes), notch of silicle acute (not shallow).

Iberis saxatilis subsp. magnesiana is separated from I. saxatilis subsp. cinerea ( Poiret 1813: 133) Font Quer (1946: 135) more easily—by its shorter 1.5–8 cm, (not up to 40 cm) flowering stems, retrorsely setulose, most dense at the top (not densely pubescent throughout) stems, leaves densely setulose on both surfaces (not densely pubescent), inflorescence corymbose in flower but elongating in fruit (not racemose in flower but widening in fruit), erect (not patent) sepals.

I. saxatilis subsp. magnesiana is morphologically separated from I. saxatilis subsp. longistyla ( Ančev 2006: 363) by retrorsely setulose indumentum of stem increasing from base to the top (vs. lacking in subsp. longistyla ), leaves densely setulose on both surfaces (not more or less puberulent), sepals 2.2–4 mm, purplish, setulose (not 1.5–2.5 mm, green to purplish, glabrous), petals inner 4.5–6 mm, outer 6.5–7.5 mm (not inner 3.5–4.5 mm, outer 5–6.5 mm), style 0.8–1.2 mm (not 1.5–2.0 mm), fruit greenish to purplish, ovate to suborbicular, rounded at base, apically with 2 rounded lobes (not broadly winged from the base, with rounded lobes), acute (not shallow) notch of silicle.

Figures

FIGURE 1. Iberis saxatilis subsp. magnesiana, a—habit; b—petals; c—flower; d—inner flower; e—outher flower; f, g—sepals; h— pistil; i—fruit; j, k—leaf (illustrated by Cem Azeri).

FIGURE 2. Iberis saxatilis subsp. magnesiana, a—habitat; b—flowering period; c—fruiting period.