Rhabdosciadium hizanense Fırat & Güzel, 2019

Firat, Mehmet & Güzel, Yelda, 2019, Contributions to the taxonomy of the Irano-Turanian genus Rhabdosciadium (Apiaceae): Nomenclatural notes, carpology, molecular phylogeny and the description of a new species from Bitlis (Turkey), Phytotaxa 395 (3), pp. 179-198 : 182-185

Rhabdosciadium hizanense Fırat & Güzel sp. nov. ( Figs. 4‒8 )

Type: — TURKEY. B 9 Bitlis: Hizan Province, İhtiyarşahap Mountains (Lolan hill), Mêrga Mehîr plateau, rocky, stone, and calcareous areas, 2221 m, 38°21′38″N, 42°25′39″E, coll. 2 August 2015, M. Fırat 32618 (holotype: VANF, isotypes: HUB, ANK and Herb. M. Fırat).

Diagnosis: —The new species is morphologically most closely related to R. anatolyi due to short and wide leaf segments, but differs from it by its 4‒10 × 2‒5 cm leaves (vs. 14‒50 × 6‒15 cm); lanceolate or ovate leaf segments (vs. elliptic or rhomboid), bluish-green appearance (vs. pale green), caespitose habit with dense basal leaves (vs. erect, loose clusters of basal leaves), compound umbels (vs. paniculate-corymbose with some proliferating umbels) and plant height 5‒40 cm (vs. 70‒170 cm).

Description: —Perennial, herbaceous, glaucous, and bluish-green plants with taproot 4‒10 × 0.5‒2 cm, and with simple or closely branched 4‒7 × 1‒2.5 cm caudex. Caudex covered with a dense fibrous collar. Stems 5‒40 cm tall, ca. 2 mm at base, dichotomously branched from the middle part of the stem, solid and slightly striate, densely caespitose with sterile shots and dense basal leaves. Basal leaves 1-pinnate, 4‒10 × 2‒5 cm with petiole. Petiole 2‒5 cm, sheathing at base. Sheaths deltoid, 0.5‒1 cm, with hyaline margin 0.7 mm wide. Segments of the basal leaves lanceolate or ovate with regularly serrate margin, 1.5‒2 × 0.5‒1 cm, all sessile. Terminal segment of the basal leaves similar to the lateral ones or tripartite with 1.2‒1.5 × 0.2‒0.5 cm subsegments. Cauline leaves gradually reduced; middle cauline leaves ca. 2 cm long, 1-pinnate or tripartite lamina with 0.4 × 0.2 cm lanceolate to linear segments. Upper cauline leaves bracteiform (prophyll-like), 0.5‒1 cm, completely membranous. Peduncle ca. 2 cm in flowering and ca. 8 cm in fruiting stages. Prophylls 0‒1. Inflorescence a compound umbel. Rays 5‒9, subequal, ca. 0.5 cm in flowering and ca. 2.5 cm in fruiting stages. Pedicels of peripheral male flowers 4‒9, subequal, up to 3 mm; central hermaphrodite fertile flower sessile. Bracts 1‒4, persistent, membranous with brown line, lanceolate to filiform, 1.5‒3 × 0.5 mm. Bracteole persistent, 1‒2, membranous with brown middle line, acuminate 1.5‒2 × 0.1 mm. Flowers 4‒9 per umbellule. Marginal flowers male, only the central, sessile flower hermaphrodite, producing a fruit. Petals white, minute, incurved and glabrous. Sepals reduced. Anthers pinkish-purplish to whitish, 3 mm. Stylopodium conical, not embedded, 0.7 mm. Mature fruits oblong, not curved or occasionally slightly curved in some umbellules (fruit curved when one of the mericarps is not fully developed); one central sessile fruit per umbellule. Both mericarps or occasionally one of them well developed, 13‒15 × 3 mm, glabrous. All mericarp ridges are filiform but conspicuous. Styles 2‒3 mm. Primary ridges of the mericarp producing finger-like projections in the cross sections.

Phenology: —Flowering from July to August and fruiting from August to September.

Vernacular name: — Rhabdosciadium hizanense is called “Ardek” by the local people in the Hizan district of Bitlis in Kurdish. Rhabdosciadium species are also known by the local people by many names in Kurdish, e.g., “Corix”, “Xandoq” ( Fırat 2013).

Etymology: —This epithet “ hizanense ” recalls the Hizan district of Bitlis, where the new species was found.

Ethnobotanical usage: — Rhabdosciadium hizanense is collected by the local people to make brooms. It is also a fodder for grazing cattle and sheep.

Habitat and ecology: —The species is perennial and grows on the rocky, stony, and calcareous areas at an elevation of 2221 m with plants such as Prangos pabularia Lindley (1825: 7) Prangos platychlaena Boissier (1860: 457) , Pimpinella kotschyana Boissier (1844: 133) , Bunium cylindricum Drude (1898: 194) , or Campanula stricta Linnaeus (1762: 238) .

Distribution and proposed conservation status:— Rhabdosciadium hizanense only occurs on the İhtiyarşahap Mountain (Hizan/ Bitlis) and can be considered endemic to eastern Anatolia. It represents an Irano-Turanian mountain element. The distribution area of R. hizanense covers less than 20,000 km 2. The species was collected from one locality where about 5000 individuals occur. Some anthropogenic or grazing effects were observed on the population. According to the IUCN (2016) criteria and categories, we here assess R. hizanense as Vulnerable (VU).

Figures

FIGURE 4. Rhabdosciadium hizanense in habitat (from the holotype, M. Fırat 32618).

FIGURE 5. Habit of Rhabdosciadium hizanense (from the holotype, M. Fırat 32618).

FIGURE 6. Caudex of Rhabdosciadium hizanense (from the holotype, M. Fırat 32618).

FIGURE 7. Umbel of Rhabdosciadium hizanense (from the holotype, M. Fırat 32618).

FIGURE 8. Umbels, fruits, and leaves of Rhabdosciadium hizanense (from the holotype, M. Fırat 32618).