Abies borisii-regis is a species of fir

Fir

Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...

 native to the mountain

Mountain

Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...

s of the Balkan Peninsula, in Bulgaria

Bulgaria

Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...

, northern Greece

Greece

Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

, the Republic of Macedonia

Republic of Macedonia

Macedonia , officially the Republic of Macedonia , is a country located in the central Balkan peninsula in Southeast Europe. It is one of the successor states of the former Yugoslavia, from which it declared independence in 1991...

, Albania

Albania

Albania , officially known as the Republic of Albania , is a country in Southeastern Europe, in the Balkans region. It is bordered by Montenegro to the northwest, Kosovo to the northeast, the Republic of Macedonia to the east and Greece to the south and southeast. It has a coast on the Adriatic Sea...

 and Serbia

Serbia

Serbia , officially the Republic of Serbia , is a landlocked country located at the crossroads of Central and Southeast Europe, covering the southern part of the Carpathian basin and the central part of the Balkans...

. It occurs at altitudes of 800-1,800 m, on mountains with a rainfall of over 1,000 mm.

It is a large evergreen

Evergreen

In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 coniferous tree

Tree

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

 growing to 40-50 m (exceptionally 60 m) tall and with a trunk diameter of up to 1.5 m. The leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 are needle-like, flattened, 1.8-3.5 cm long and 2 mm wide by 0.5 mm thick, glossy dark green above, and with two blue-white bands of stomata below. The tip of the leaf is variable, usually pointed, but sometimes slightly notched at the tip, particularly on slow-growing shoots on older trees. The cones

Conifer cone

A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...

 are 10-21 cm long and 4 cm broad, with about 150-200 scales, each scale with an exserted bract and two winged seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s; they disintegrate when mature to release the seeds.

It is closely related to (and in many respects intermediate between) Silver Fir

Silver Fir

Abies alba, commonly known as the European silver fir, is a fir native to the mountains of Europe, from the Pyrenees north to Normandy, east to the Alps and the Carpathians, and south to southern Italy and northern Serbia.-Description:...

 to the north in central Europe, Greek Fir

Greek Fir

Greek Fir is a fir native to the mountains of Greece, primarily in the Peloponnesos and the island of Kefallonia, intergrading with the closely related Bulgarian Fir further north in the Pindus mountains of northern Greece. It is a medium-size evergreen coniferous tree growing to – rarely – tall...

 to the south in southern Greece, and Nordmann Fir

Nordmann Fir

Nordmann Fir is a fir native to the mountains south and east of the Black Sea, in Turkey, Georgia, Russian Caucasus and northern parts of Armenia. It occurs at altitudes of 900-2,200 m on mountains with a rainfall of over 1,000 mm.It is a large evergreen coniferous tree growing to 60 m tall...

 to the east in northern Turkey

Turkey

Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

. Some botanists treat it as a natural hybrid between Silver Fir and Greek Fir, while others treat it as a variety on Silver Fir, as Abies alba var. acutifolia. Another synonym is Abies pardei.

The scientific name honours Tsar Boris III of Bulgaria

Boris III of Bulgaria

Boris III the Unifier, Tsar of Bulgaria , originally Boris Klemens Robert Maria Pius Ludwig Stanislaus Xaver , son of Ferdinand I, came to the throne in 1918 upon the abdication of his father, following the defeat of the Kingdom of Bulgaria during World War I...

, during whose reign it was described as a new species in 1925. The name is sometimes cited without a hyphen (Abies borisiiregis), though under the provisions of ICBN Article 60.9 the hyphen is to be retained.