Carpinus austrobalcanica


Carpinus austrobalcanica, the southern Balkan hornbeam, is a species of hardwood tree in the family Betulaceae, subfamily Coryloideae, native only to the southern Balkan Peninsula, in particular southern Albania and northwestern Greece. First described in 2024 it is, with the European hornbeam and the Oriental hornbeam , one of three hornbeams native to Europe.

Description

C. austrobalcanica is a deciduous tree reaching heights up to 15 meters. It is "closely related" to, but differs from the similar common European hornbeam in a number of characters. Differences can be observed in the structure and colour of the bark, which is deeply fissured into centimetre-sized scales, and light brown to brown. In this respect, C. austrobalcanica is more similar to European hophornbeam. Additionally, the buds are obovate, while those of common hornbeam have a pointed shape.
The leaf structure also varies, with Carpinus austrobalcanica having a flat leaf surface that is not wavy, while the other species has strongly wavy leaves. The leaf venation in C. austrobalcanica is not pronounced and more or less in the plane of the leaf surface. In contrast, common hornbeam has a pronounced venation.
The Inflorescences of C. austrobalcanica are very elongated, up to 25 cm, interrupted, and usually clearly longer than the supporting leaf, those of common hornbeam are dense, up to 15 cm, rarely clearly interrupted, and usually only slightly longer than the supporting leaf.

Evolution

Within Carpinus, C. austrobalcanica is most closely related to the European hornbeam, but is distinct not only in morphology, but also in its genome. Based on the European hornbeam's evolutionary origin in the Pliocene, C. austrobalcanica is assumed to have diverged from that species in the late Pliocene or early Pleistocene, a divergence that was accompanied by an adaptation to different, more thermophilous ecological conditions.

Distribution and habitat

C. austrobalcanica is currently known only from a limited range in the northern Pindus of Albania and Greece, specifically the Nemërçka and Tymphe mountain ranges. Here it occurs at altitudes ranging from 850 to 1500m in mixed to almost monodominant stands, in xero-thermophilous communities along with oaks, other Coryloidae, maples, rosaceous species, broad-leaved lime, cade juniper, Judas tree and tanner's sumach, on calcareous soils.

Discovery

The species was first described in 2024 by scientists from University of Belgrade and University of Innsbruck.