# Southern Balkan Hornbeam

The Southern Balkan Hornbeam (carpinus austrobalcanica) is a species of tree in the family corylaceae, only native to southern Balkan Peninsula in Southern Albania and Northwestern Greece. This hardwood tree belongs to the plant genus carpinus in the family betulaceae.
It is first described 2024 and one of three Hornbeams original in Europe, together with European hornbeam (carpinus betulus) and Oriental hornbeam (carpinus orientalis).

## Description

It is a deciduous tree reaching heights up to 15 meters. The bark is light brown to greyish brown, with vertical, a few centimetres long plates; on old trees usually covered with a thick layer of mosses and lichens. The branchlets are reddish-brown, glabrescent, often with many prominent white lenticels. The buds are obovate, with hirsute or ciliate scales with light margin, up to 10.9 mm long and 4.8 mm wide.
The petioles are villous to glabrescent. Stipules are light brown to reddish-brown, equal or longer than the petiole, often remaining on the branchlets until autumn. The leaves are alternate, leaf blade broadly elliptic to ovate-elliptic, 5.7–9.8 cm long and 3.3–6.1 cm wide.
The leaves are more or less leathery, abaxially sparsely villous along veins, sparsely bearded in axils of lateral veins, base rounded, rounded-cuneate or cordate, margin regularly or irregularly and doubly minutely serrate, apex acuminate; lateral veins not prominent, more or less at the level of the leaf surface (not raised abaxially, and not significantly impressed adaxially).
Female inflorescences are terminal or axillary on short shoots, racemose; flowers paired. Bracts are 3-lobed, complanate, overlapping margin of lobes entire or rarely serrate. All lobes are entire at the margin, rarely with a few small teeth. Infructescence pendulous, in late fruiting stage up to nearly 25 cm long; peduncle 5.5–28.1 mm long. Nutlets ovoid-ellipsoid, 7.2–10.3 mm long and 6.4–7.2 mm wide, glabrous, brown, prominently 6 or 9-ribbed, at the apex with several teeth.

## Distribution

Carpinus austrobalcanica is restricted to the Mt. Nemërçkë (Dousko) in Albania (Mali I Dembeli above Lipa and slopes above Skore) and Greece (around Kefalovryso), and on Mt. Tymphe (around Mikro Papigko) in Greece. The populations develop on carbonates and are found at altitudes ranging from 850 to 1500 meters.
| Tree | Trunk (with moss) | Bark (with moss and lichens) | Leaves und inflorescences | inflorescence |

## Ecology

Carpinus austrobalcanica occurs in various types of deciduous forests and thickets. It inhabits supramediterranean xero-thermophilous oak-hornbeam-hop hornbeam forests on shallow calcareous soils on steep slopes in the upper montane belt (Quercetalia pubescenti-petraeae Klika 1933).
In some areas, it forms almost monodominant stands, while in others it grows in mixed communities with other woody species such as Acer monspessulanum L., Carpinus orientalis, Juniperus excelsa M. Bieb., Ostrya carpinifolia, Prunus mahaleb L., Quercus petraea (Matt.) Liebl., Quercus pubescens Willd., Quercus trojana Webb, and others. In the Albanian part of the range, carpinus austrobalcanica is part of open or closed xerophilous thickets with Cercis siliquastrum L., Haplophyllum albanicum (Bald.) Bornm., Ostrya carpinifolia, Rhus coriaria L., Sorbus graeca (Spach) Schauer, and others. On Mount Tymphe, carpinus austrobalcanica occurs in submediterranean xero-thermophilous broad-leaved scree and ravine forests together with Acer pseudoplatanus L., Carpinus orientalis, Juniperus oxycedrus L., Ostrya carpinifolia, Tilia platyphyllos Scop., and others.

## Discovery

The Southern Balkan Hornbeam was first described 2024 by scientists from University of Belgrade and University of Innsbruck.