Species Spotlight: Quercus carduchorum K.Koch

Parisa Panahi¹ and Mehdi Pourhashemi²

¹ National Botanical Garden of Iran, Botany Research Division, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
² Forest Research Division, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

Introduction

The taxonomy of Quercus is extremely complex (Burger 1974). This genus includes evergreen and deciduous shrubs and trees extending from cold latitudes to tropical Asia and the the Americas. It is the most common genus of Fagaceae in forests of Iran. The taxa that belong to the Q. libani complex are distributed in the northern Zagros forests in western Iran. Parsa, in Flore de l’Iran (1949), recognized two taxa including Q. libani Oliv. and Q. libani Oliv. var. vesca (Kotschy) Boiss. from Zagros forests of Iran. Bobek (1951) reported only one species, Q. libani, from this group of oaks in Zagros forests. Djavanchir-Khoie, in Les Chênes de l`Iran (1967), considered 12 species within the Q. libani complex, one of which was Quercus carduchorum³ K.Koch. Menitsky, in Flora Iranica (1971), based on an examination of herbarium specimens, reported only Q. libani from this group and synonymized other species as Q. libani. Panahi et al. (2012) confirmed the presence of 5 species within the complex of Q. libani in the northern Zagros forests of Iran by studying the morphological and micromorphological characteristics of leaves and pollen grains.

Quercus carduchorum was described in 1849 by Karl Koch from Isauria (an ancient region of Asia Minor, southwestern Anatolia), at an elevation of 1,350 m. However, Koch did not provide a complete description for this species, though he collected the first specimens. In 1859, Theodor Kotschy collected complete specimens of this species from the forests of Kurdistan in Turkey, and named them Q. tchihatchewi Kotschy. In 1967, Djavanchir-Khoie reported Q. carduchorum for the first time from the Zagros forests of Iran (the forests of Marivan in Kurdistan province). The description was based on a specimen in the Geneva herbarium collected by Kotschy and personal specimens from the Baneh forests near the Iraqi border in 1963. He wrote in his PhD thesis about the abnormal leaves of this species. Djavanchir-Khoie studied all oak species in Zagros forests during 4 years (1964-1967) and his research is the first and the most complete study of Quercus in Iran. He, like Koch and Kotschy, conducted field research for a long time. Kotschy also wrote in Die Eichen Europa's und des Orient's (1862), that after collecting the acorns of some oaks in Kurdistan in fall, he stayed there until spring to observe their flowers.

A preserved specimen of Q. carduchorum collected by Djavanchir-Khoie (as "J. Djavanchir") is in the Herbarium of Université de Montpellier, Institute de Botanique (MPU). It is shown in Figure 1.

Distribution area

Currently, the distribution of this species, as an endemic species of Iran, has been reported only from the Northern Zagros forests (West Azerbaijan and Kurdistan provinces). It is  found in many forest areas of Marivan (Chenareh, Doveyseh, Gomareh Lang, Bakhan, Bardehrasheh), Baneh (Gandoman, Mirhesam, Armardeh, Kandeh Sureh, Nizeh Rood), Sardasht, Mirabad and Piranshahr forests (Figs. 2, 3).

In the flora of Turkey, where this species was reported for the first time, it is treated as a synonym of Q. libani (Davis 1982).

Botanical description

Annual branches, leaves, and buds are densely yellowish-brown tomentose. The trunk bark is furrowed with prominent scales (Fig. 4). Leaf shape is lanceolate with an almost rounded base, apex acute, with margins bearing small, very sharp teeth with a 2-3 mm mucron. Leaves have irregular and deep lobing (Figs. 5a and 5b). Upper surface of leaves is green and lower surface slightly paler. Twigs are slender and reddish-brown. The number of stamens is often 4 and sometimes 5. Stipules are deciduous. Main vein in leaves is straight. Secondary veins are parallel and of uniform length. Number of secondary veins 10-13 (often 12). Cupules are very elongated, covering at least two-thirds of the acorn. The base of the cupule is very convex, with elongated scales. Cupule scales arranged in 9-10 spirals. Acorns are cylindrical, scar barely convex and not bordered by a colored line (Fig. 6).

Quercus libani In terms of micromorphological features, this species is characterized by its dense indumentum consisting of different types of trichomes on both sides of the leaves. The density of trichomes is higher on the upper surface. Based on the morphology of leaves and fruits and micromorphology of pollen grains and leaf trichomes, Q. carduchorum has been recognized as a distinct species from Q. libani.

Silvicultural characteristics

Quercus carduchorum is a deciduous small tree up to 10 m tall (8-10 m). This species does not usually form pure stands and is observed as individuals in stands of Q. libani. In mixed forests, there are fewer individuals of Q. carduchorum than of Q. libani. Most of the trees are in the medium-sized DBH class (20-40 cm), but a variety of small diameter and thick stems can also be observed in different areas of northern Zagros. Reproduction in this species, like other species in this group, is mainly asexual.

IUCN Red List status

Currently, the conservation status of this species is Data Deficient (DD) according to the IUCN RedList. Considering the severe degradation of Zagros oak forests, it is essential to reevaluate its conservation status. A forest survey was carried out in 2011. Based on the extent of occurrence, area of occupancy, and number of mature individuals, its conservation status will likely be reassessed as Endangered.

Suggestions for conservation

• New field surveys for identifying Q. carduchorum sites in forests of Kurdistan and West Azerbaijan provinces
• Mapping the distribution 
• Estimating the number of mature individuals
• Evaluating the status of degradation and the silvicultural characteristics of the sites where it is found
• Reassessment of conservation status based on IUCN criteria
• Collecting pollen for preservation in pollen banks
• In-situ and ex-situ conservation programs

Conclusion

Given that the largest variety of oak taxa in Iran is found in the forests of Zagros (especially northern Zagros), the forests of this region constitute an important hotspot of oak-forest diversity. Unfortunately, Northern Zagros forests are severely degraded. If this trend continues, we will lose a considerable portion of these woodlands. Therefore, identifying threatened species of oak and determining their conservation status is essential for their conservation programs.

Works cited

Bobek, H. 1951. Die natürlichen Wälder und Gehölzfluren Irans. Bonner Geographische Abhandlungen 8. Bonn: Selbstverlag des Geographischen Instituts der Universität Bonn. [link]

Burger, W.C. 1974. The species concept in Quercus. Taxon 24: 45-50. [link]

Davis, P.H. 1982. Flora of Turkey and the East Aegean Islands. Vol. 7. Edinburgh: Edinburgh University Press.

Djavanchir-Khoie, K. 1967. Les chênes de l`Iran. PhD thesis. University of Montpellier, Montpellier, France.

Koch, K. 1849. Beiträge zu einer Flora des Orientes. Linnaea 22(3): 177-596.

Kotschy, T. 1862. Die Eichen Europa’s und des Orient’s. E. Hölzel, Wien und Olmütz.

Menitsky, G.L. 1971. Fagaceae. In: Rechinger, K.H., editor, Flora Iranica (Vol. 77: 1–20). Graz: Akademische Druck- u. Verlagsanstalt.

Panahi, P., Z. Jamzad, M.R. Pourmajidian, A. Fallah, and M. Pourhashemi. 2012. Taxonomic implications of micro-morphological features for taxon delimitation within the Quercus libani complex (Fagaceae) in Iran. Phytologia Balcanica 18(3): 263-276.

Parsa, A. 1949. Flore de l’Iran: Fagaceae (Vol. 4: 1319–1332). Tehran: Imprinerie Mazaheri.

³ The epithet carduchorum means “of the Carduchii”, referring to the group of warlike tribes, also known as Karduchoi, that inhabited the area known as Kurdistan, including present-day southeastern Turkey, northern Iraq, northwestern Iran, and northern Syria. Karl Koch was the first author to use this epithet in 1849, when he published three names that used it: Allium carduchorum, Heliotropium carduchorum, and Quercus carduchorum. In all cases, the specimens described had been collected in what was then referred to as Kurdistan.

Photos © Parisa Panihi