Abies x borisii-regis

Pinaceae Abies x borisii-regis Mattf.

Etymology
Abies refers to ‘to rise’; indicating large trees.
borisii-regis refers to King Boris of Bulgaria.

Colloquial Name
King Boris fir, Bulgarian fir, Macedonian fir

Description
These trees can grow up to 40 meters tall, with trunks reaching 1.5 meters in diameter. The trunk is straight, cylindrical, and supports a conical crown, though older trees often develop a flattened top that resembles a stork’s nest. Young trees have smooth, grayish bark, while mature trees have bark that turns grayish-brown, varying from light to dark, and becomes scaly and cracked at the base.

The main branches extend horizontally, with the lower ones drooping slightly before curving upward toward the top. Smaller branches are slender and spread out horizontally. The twigs are flexible and thin but sturdier on cone-bearing branches. Their color ranges from yellowish-gray to gray, with a nearly smooth texture that has faint ridges and a fine layer of short yellow or brown hairs. The scars left by fallen leaves are broad and either circular or elliptical in shape.

The buds are oval or cone-shaped, about 6 mm long and 4 mm wide, and are either dry or slightly sticky with resin, especially on cone-bearing branches. The scales covering the buds are broad and oval, with rounded tips, and remain on the tree for several years, turning brown over time. The needles grow in a spiral pattern. On vegetative branches, they spread out in two neat rows along the sides. On fast-growing shoots, they radiate outward in all directions, and on cone-bearing branches, they are both radial and upward-pointing. They range from 1.2 to 3.5 cm long and 1.5 to 2.6 mm wide, with slightly twisted bases. Each needle is long, flat, and grooved, with a glossy dark green surface on top and a pale green underside. The tip is smooth and unnotched. Tiny openings called stomata, which help with gas exchange, form two bands on the lower surface, with a few sometimes appearing on the upper side as well.

The pollen cones grow in clusters and are about 2 cm long. They are greenish-yellow with small purple-red structures that produce pollen. The seed cones grow upright on short, slightly curved stalks. They are cylindrical, with a rounded or slightly pointed tip, measuring between 10 and 20 cm long and 3 to 6 cm wide. When young, they are yellowish-green, sometimes with a purple tint, and later ripen to a light brown or reddish-brown. After the seeds are released, the central axis of the cone remains on the tree, forming a narrow, cone-shaped structure that turns dark brown.

The cone scales are shaped like small cups, with the upper ones being more wedge-shaped. In the middle of the cone, they measure 2.5 to 3 cm in length and 2.5 to 3.5 cm in width. The surface is smooth and has a powdery texture, especially on the exposed part. The upper edge is unbroken, and the base is attached to a long stalk. The bracts inside the cone are long and narrow, with a slightly spoon-like shape and a long, tapering tip. They measure between 2.5 and 4 cm in length, extend beyond the cone’s surface, and curve slightly backward when mature.

The seeds are wedge-shaped with angular sides, measuring 7 to 9 mm long and yellowish-brown in color. They have broad, wedge-shaped wings that are 10 to 15 mm long and reddish-yellow, which help them disperse in the wind.

Distribution

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TDWG Codes
1, 13, ALB, BUL, GRC

Habitat
The natural habitats for Abies x borisii-regis are unknown. The natural elevation is unknown. There are no conifers associated with Abies x borisii-regis that are known of.

USDA Hardiness zone – 6
Abies x borisii-regis is hardy to USDA Zone 6 (Bannister & Neuner, 2001), meaning its frost tolerance lies somewhere in the range of -23.3C (-10F) to -17.8C (0F).

Species Continuity
The population trend for Abies x borisii-regis is unknown. There are no known threats for Abies x borisii-regis.

IUCN Category – NE
According to the IUCN Red List, Abies x borisii-regis has been assigned the status of NE(Not Evaluated). This means that there has not been made an assessment of its status.

Superordinate Taxa
The nearest superordinate taxon for Abies x borisii-regis is Sect. Abies. The coordinate taxa for Abies x borisii-regis are therefore:

Abies x borisii-regis is further placed under Abietoideae. Abies x borisii-regis is also placed under Pinaceae.

This map shows botanical records (points) for this taxon. By opening the map’s sidebar (collapsed by default) you can toggle visibility or change the basemap. By clicking on records, you reveal more information.

Cultivars
‘F.R. Newman’, ‘Greece’, ‘Pendula’, ‘Spring Delight’