Prunus longispinosa (Rosaceae): a new species from Kurdistan, Iraq

Pak. J. Bot., 52(2): 645-651, 2020. DOI: http://dx.doi.org/10.30848/PJB2020-2(36) PRUNUS LONGISPINOSA (ROSACEAE): A NEW SPECIES FROM KURDISTAN-IRAQ SHAMIRAN SALIH ABDULRAHMAN1 AND SALEEM ESMAEL SHAHBAZ2* College of Science, University of Zakho, Duhok, Kurdistan – Iraq College of Agriculture, University of Duhok, Duhok, Kurdistan – Iraq * Corresponding author’s email: [email protected] 1 2 Abstract Prunus longispinosa S.E. Shahbaz and S.S, Abdulrahman (Rosaceae), a new species from Kurdistan-Iraq, is described and illustrated. It differs from all Iraqi taxa of the subgenus Amygdalus by the dark reddish color of their one-year-old twigs and the very whitish thorny branches. The new species is closely related to P. spinosissima but can be easily separated by its green drupes vs. reddish drupes from one side and green from the other. The new species also shows close resemblance to Prunus lycioides but the later differs from it in having one reddish side and pale green side of their one-year-old twigs and glabrous drupes vs. dark reddish color of their one-year-old twigs and pubescent drupes for the new species. Key words: Prunus spinosissima, Prunus lycioides, Prunus carduchorum, Subgenus Amygdalus, New species, Drupe, endocarp. Introduction While treating the woody plants of Rosaceae family, Schneider (1906) distinguished three genera, namely, Prunus, Padus, and Laurocerasus. He also recognized within Prunus the three subgenera: Euprunus, Cerasus, and Amygdalus. Five subgenera: Amygdalus, Prunus, Cerasus, Padus, and Laurocerasus were identified by Rehder (1940); while Okie (2003) recognized six subgenera when Lithocerasus was added to the 5 subgenera of Rehder. Some other workers recognized six to ten genera (De Tournefort, 1700; Roemer, 1847; Yu et al., 1986; Takhtajan, 1997) within the generic concept of Prunus s.l. In Iraq, Townsend & Guest (1966) recognized the single genus Prunus within the subfamily Prunoideae Focke, and subdivided it on the basis of reproductive and vegetative morphological characters into subgenera Prunus L. Amygdalus (L) Focke, and Cerasus Pers. The Plant List version 1(2010) accepts 88 out of 482 specific names for the genus Prunus, in addition to the 213 infra-specific taxa for the same genus, all are spreading throughout the northern temperate regions of the world. According to the treatment used, Browicz (1969), Yazbek & Oh (2013), Vafadar et al., (2014) accepted 24 to 45 almond species. For Zhukovshy (1971), Browicz & Zohary (1996), Gradziel (2010), and Vafadar et al., (2010), the highest diversity of subg. Amygdalus species occurs in southwestern and central Asia, and in the Irano-Turanian phytogeographic region of which northern Iraq is part. Based on morphological characters, De Tournefort (1700) recognized Prunus and Amygdalus, as separate genera. Some botanists inclined to split Prunus s.l. into numerous genera (Yu et al., 1986; Takhtajan, 1997; Lu & Bartholomew, 2003), while others preferred to maintain the unity of Prunus s.l and only identifying sectional or subgeneric groups (Chin et al., 2010; Shi et al., 2013; Eisenman, 2015). Recent phylogenetic analyses of molecular data have shown Prunus s .l. to be monophyletic (Bortiri et al., 2001). Moreover, in a recently presented monograph using morphological and molecular sequence data, Yazbek (2010) concluded that phylogenetic relationships of Prunus subg. Amygdalus is best circumscribed to include almonds and peaches. Flora of Iraq is rich in Prunus taxa, 5 wild species of the subgenus Amygdalus are present ((P. arabica (Oliv.) Meikle. P. webbii (Spach) Vierh. P. argentea (Lam.) Rehd, P. kotschyi (Boiss. et Hoh.) Meikle, and P. carduchorum (Bornm) Meikle)) together with several other ill-defined infra-specific taxa((P. argentea var. elaeagnifolia (Spach) Meikle, and P. carduchorum var. glabra (Bornm) Meikle)) which form the bulk of food source for honey bees at the time of flowers scarcity in Winter and in very early Springtime. Members of the subgenus Amygdalus: Prunus persica (L.) Batsch. and P. dulcis are extensively cultivated in orchards and vineyards throughout Iraq, but all other taxa are growing naturally in the mountainous region at the upper forest zone, timber-line and even in the thorncushion zone, usually at high altitudes up to 1800m. Two species; namely, P. argentea and P, arabica are normally found in the lower forest zone. Moreover, P. arabica is growing in the steppe and sub-desert regions of Iraq down to 150m above sea level. Material and Methods Field trips were conducted in Sulaymani province/ Kurdistan region with the aim of collecting Prunus plants. Trips started September 25/2016, continued at April to June 2017. Authors collected specimens belonging to Prunus subgenus Amygdalus from Hanaqol Mountain east of Khormal town, near Iranian border facing Mariwan city, revisited in March 20/2017 to collect flowers and then in May 25/2017 to collect fruits. The specimens were compared with all Prunus specimens in Iraqi herbaria including National Herbarium of Iraq/Baghdad (BAG), Sulaymani University Agriculture Herbarium (SUAH), and Kurdistan Botanical Foundation Herbarium (KBFH) in Sulaymani. Moreover, the specimen photos were sent to Herbarium of the Hebrew University of Jerusalem (HUJ), Central Herbarium of Tehran University (TUH). Records in the literature (Shaw, 2005; Sangtae & Jun, 2001; Yazbek, 2010) were checked. Flora of Iraq (Townsend & Guest, 1966) and the neighboring countries: Flora of Turkey (Davis, 1965-1988) and flora of Iran (Rechinger, 1963-2005) were consulted. 646 S.S. ABDULRAHMAN & S.E. SHAHBAZ The unknown Prunus is found only in one location, an effort to find more locations in the vicinity where this novel plant may be located was unsuccessful. Morphological measurements for the description of the taxa were obtained from observation of living material in the field and occasionally from herbaria. 12 herbarium specimens were prepared from similar number of the new species and deposited in DPUH (Duhok Province University Herbarium). Results and Discussion Prunus longispinosa S.E. Shahbaz, and S.S. Abdulrahman, Species Nova. Type: Iraq, Kurdistan, Sulaimani province, 2.5-3km east Khormal city, the south-east facing of Hanaqol Mountain, Hanaqol village, spreading in an area of about 2.4 x 0.6 km, in a steep rocky slope, altitude 1095m, latitude 35.31995°N, longitude 46.06223ºE. Sept, May 25/2017. Saleem Esmael Shahbaz (University of Duhok), Shamiran Salih Abdulrahman (University of Zakho), 2017-3630. Holotype: DPUH, Isotype: KBFH (Kurdistan Botanical Foundation Herbarium), (Table 1; Fig. 1). Diagnosis: Plants are shrubs characterized by thorny branches; thorns whitish, very sharp, 1.6-5.8cm long; oneyear-old twigs deep-reddish, older grey whitish. Leaves are mostly falcate or curved. Hypanthium tube is long, up to 9mm length. Drupes are very small, 8.5-16mm length x 6-10.5mm width x 5.2-7mm thickness; endocarp pits absent; furrows start from the base becoming shallower towards the apex. Table 1. Additional specimens studied. Place Date Specimen number Herbarium deposited Altitude m, above sea level Collector Growth stage 1. Iraq/ Sulaymani/ Hanaqol Mar.17/2016 3046 DPUH 1095 Shamiran Flowering 2. Iraq/ Sulaymani/ Hanaqol Mar.17/2016 3645 DPUH 1102 Shamiran Flowering 3. Iraq/ Sulaymani/ Hanaqol May.2/2016, 3695 DPUH 1105 Shamiran & Saleem Fruiting 4. Iraq/ Sulaymani/ Hanaqol July 19/ 2016 3056 DPUH 1097 Shamiran & Saleem Fruiting 5. Iraq/ Sulaymani/ Hanaqol Sept, 25/2016 3057 DPUH 1106 Shamiran Fruiting 6. Iraq/ Sulaymani/ Hanaqol April 4/ 2017 3677 DPUH 1109 Shamiran Flowering 7. Iraq/ Sulaymani/ Hanaqol April 4/ 2017 3678 DPUH 1384 Shamiran Flowering 8. Iraq/ Sulaymani/ Hanaqol April 4/ 2017 3679 DPUH 1137 Shamiran Flowering 9. Iraq/ Sulaymani/ Hanaqol Sep. 10/2017 3680 DPUH 1121 Shamiran Fruiting 10. Iraq/ Sulaymani/ Hanaqol Sep.10/2017 3681 DPUH 1272 Shamiran Fruiting Fig. 1. Map of northern Iraq showing the location of Prunus longispenosa. 647 PRUNUS LONGISPINOSA (ROSACEAE): A NEW SPECIES Species description: Shrubs are 0.65-1.22 m tall, with spreading crown. Bark grey, with black lenticels, upper parts grey whitish. Branches very thorny, some ascending, others trailing; thorns whitish, 1.6-5.8cm long; one-yearold twigs deep-reddish, glabrous. Axillary buds with scale margin entire, glabrous, apex rounded, base cuneate. Leaves mainly born on new growths, few on old twigs, mostly present as short shoots of 1.7-7 mm long, fascicled, 6-25mm long, 2-4.5mm width; blade shape mostly falcate or curved; lanceolate to oblanceolate, narrow-elliptic; apex acute to acuminate; base cuneate to more or less rounded, glabrous; margins obscurely serrate, more towards apex, 79teeth per cm, each with a single gland; petiole very short 1-2mm; stipules caduceus. Inflorescences fascicled on short shoots; pedicel 0-1,5mm long, flowers with hypanthium red-purple, cylindrical, inflated at the base. 4.5-9mm long, 0.5-2mm wide with 6-10 longitudinal dark colored striations, glabrous; sepals reddish from outside and inside, margins entire,ciliated,1.6-2mm long, 1.2-1.7mm wide, apex acute; petals pink to pale pink, oblong, or wedgeshaped, apex emarginated to acute, base cuneate or tapering, 6.5-8mm long, 3.5-4.5mm width; stamens 9 -18, 0.8-5mm long; style longer than stamens.4.5-7mm long, densely long-hairy at the style lower part, often persistent in fruit; ovary ovate pubescent, 1.5-3.5mm long, 1.22.9mm width. Fruits with pedicel 0.7-1.2 mm long, hairy, drupe green often asymmetrical, compressed or slightly so, 8.5-16mm long, 6-10.5mm wide, 5.2-7mm thick, ovate in cross-section; base round, sometimes slightly asymmetric; apex acute to round, surface pubescent; mesocarp splitting at complete or over maturity; endocarp brown to light brown, more or less asymmetric, ovate in cross-section, compressed, 8.5-13mm long, 5.5-9.6mm wide, 4.2-6.2mm thick, base round, sometimes slightly asymmetric, apex acute to round, surface pits absent, ventral suture with obtuse keel, furrow start from the base becoming shallower towards apex, sometimes reticulate furrows in patches or allover, could be deep or shallow. Seeds are with whitish pulp, 5-10mm long, and 3-4mm wide, and 1.4-3mm deep, ovate to oblong-ovate, base round asymmetric, apex acute or acute-mucronate; testa slightly sulcate, light brown (Figs. 2, 3, 4 and Table 3). Fig. 2. Prunus longispinosa: a. Habit and habitat, b. One-year-old twigs, c. Stems, d. Fruiting branches with thorns. Pak. J. Bot., 52(2): 645-651, 2020. DOI: http://dx.doi.org/10.30848/PJB2020-2(36) Fig. 3. Prunus longispinosa: a. leaves, b. flowering twig showing long hypanthium tube and leaves with marginal glands, c. Endocarp with distinct furrows at the base, d. Endocarp: comparison between P. carduchorum (left) and P. longispenosa (right). Distribution and conservation status: Distribution is known only in Hanaqol Mountain/ Sulaimani province, a restricted area near the Iranian border (Fig. 1). The new species is found to form a population of low density, above 1095m altitude. The area is denuded from the normal arborescent cover of Quercus and Pistacia (Pistacia eurycarpa Yal. and P. khinuk Stocks) which are normal in lower elevations. Very few perennials could be observed in the region, like Rhus coriaria L., P. cardochorum, number of Compositae as Onopordon sp. Silybum marianum (L.) Gaertn., Echinops ritro L., Centaurea sp., and Lactuca serriola L. A great number of annuals from Poaceae like Hordeum spp., Avena spp., and Bromus spp. are to be found covering the site. Some members of Apiaceae like Tordylium cordatum (Jacq.) Poir. are also common in the region. Prunus longispinosa seems to face some degradation in its habitat due to intensive grazing and gathering of firewood by the local villagers, in addition to fires that break out from time to time in the region during the long dry summer season. The spread of groups of individuals at the very high altitude of the limited area of distribution and the very steep rocky slope of some sites may cause reduction of threats to this species. Since necessary information regarding population size, number of mature individuals, reproduction status, and exact quality of habitats are not known, the IUCN Red List category (Anon., 2001) for this species remains uncertain and could currently be assessed as Data Deficient (DD). Related Taxa: Only P. longispinosa and P. carduchorum coexist at the same habitat and overlap at their area of distribution. Both show similar habit and possess mesocarp that is splitting at complete maturity and endocarp surface with no pits, but P. carduchorum branches are thorn-less and the one-year-old twigs are greenish-brown (Fig. 5). All available taxa in Iraq are thorn-less except P. argentea and the one-year-old twigs of them are not red in color at all with the exception of the new species (Table 2; Fig. 5). PRUNUS LONGISPINOSA (ROSACEAE): A NEW SPECIES 649 Fig. 4. Drupes, endocarps, and Kernels of Prunus subgenus Amygdalus growing in Iraq: 1. P. kotschyi, 2. P. arabica, 3. P. longispenosa, 4. P. carduchorum var. carduchorum, 5. P. carduchorum var. glabra, 6. P. argentea var. argentea, 7. P. argentea var. elaeagnifolia, 8. P. webbii, 9. P. dulcis. Table 2. Characteristics used to differentiate Prunus longispinosa from the two closely related species P. spinosissima (Bunge) Franch and Prunus lycioides (Spach) C.K. Schneid (Yazbek, 2010) (Fig. 5). Characters P. longispinosa P. spinosissima P. lycioides One-year-old twigs deep reddish, older One-year-old twigs deep reddish, older One-year-old twigs reddish side and pale twigs grey-whitish, with black lenticels. twigs brown-grey to white-grey, glabrous green side, older twigs grey, glabrous Shoot glabrous Falcate or curved, lanceolate to Spathulate, obovate, elliptic or Linear, linear- lanceolate, or linearLeaves oblanceolate, narrowly elliptic, 6-25 x 2- lanceolate, (11)18- 28(30) x 3 - 9mm oblanceolate, 9-32 x 1- 4 (7) mm 4.5mm Hypanthium red-purple, cylindrical, Hypanthium reddish, cylindrical, inflated Hypanthium deep-red to purple, inflated at the base. 4.5-9 mm long, 0.5- at base, 3-8 mm long, 1-3 mm wide, cylindrical, inflated at base, 3-7 mm long, Hypanthium 2mm wide with 6-10 longitudinal dark glabrous 1-3 mm wide, glabrous colored striations, glabrous Style Densely long-hairy at its lower part Not recorded Not recorded Green, 8.5-16mm long, 6-10.5mm wide, Reddish from one side and green from Green,10-17 mm long, 7-14 mm wide, 5Drupe 5.2-7mm thick, surface pubescent the other, 9-15 mm long, 9-16 mm wide, 10 mm thick, surface glabrous 8-10 mm thick, surface pubescent ovate, compressed, 8.5-13mm x 5.5- Ovate, strongly compressed, 13-14mm x ovate or broadly ovate, strongly 9.6mm x 4.2-6.2mm, surface pits absent, 9-17mm x 7-9mm, compressed, 10-16 mm x 8-13 mm x 6furrow start from the base becoming surface pits absent, shallow furrows start 10 mm, surface pits absent, furrows start Endocarp shallower towards the apex, sometimes from base becoming shallower and from the base becoming reticulate reticulate furrows in patches or allover disappear towards the apex, or reticulate towards the apex, could be deep or furrows allover could be deep or shallow shallow Flowering early March to Late April, Flowering: Late Feb to Late April; Flowering: Late Jan to Early May; Phenology fruiting: early May to Late July fruiting: Early May – Mid Aug. fruiting: Late Mar – Mid July In semi-arid to semi-humid region, in In semi-arid regions, rocky mountain In dry and semiarid regions, rocky slopes Habitat steep rocky mountain slope, elevation slopes. elevations between 700 – 1900 m. and hillsides. 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