Morphological characteristics of Pinus sylvestris var. mongolica
Camphor pine is a tree with a height of 25 meters and a diameter at breast height of 80 centimeters; The bark of a large tree is thick, and the lower part of the trunk is gray brown or black brown. It deeply cracks into irregular scaly pieces and falls off. The upper bark and branch bark are yellow to brownish yellow, and the inner side is golden yellow. It cracks into thin sheets and falls off; Branches spread diagonally or horizontally, with a pointed tower shaped crown for young trees and a dome or flat top for older ones, with sparse crowns; The annual branches are light yellow brown, and they grow gray brown in the second and third year; Winter buds are brown or light yellow brown, long oval shaped, and have resin.
Needle needles are a bundle of two needles, hard and straight, often twisted, measuring 4-9 centimeters in length, rarely up to 12 centimeters, with a diameter of 1.5-2 millimeters, a pointed tip, fine serrations on the edges, and stomatal lines on both sides; The cross-section is semi-circular, slightly flattened, with a single layer of subcutaneous cells and a transverse cocoon like vascular bundle sheath. The two-dimensional vascular bundles are far apart, with 6-11 resin channels and lateral growth; The basal part of the leaf sheath remains, black brown in color.
Male bulbous flowers are cylindrical and oval in shape, measuring 5-10 millimeters in length. They gather at the lower part of new branches and are approximately 3-6 centimeters in length; The female ball flower has a short stem, light purple brown color, and the small ball fruit that grows in the same year is about 1 centimeter long and drooping.
The cones are oval or long oval in shape, measuring 3-6 centimeters in length and 2-3 centimeters in diameter. They are green before maturity, light brownish gray when ripe, and begin to fall off after maturity; The scales in the middle of the plant are mostly oblique square shaped, with prominent longitudinal and transverse ridges, thick and raised, and often curved. The scale navel is a tumor like protrusion with short spines that are easy to fall off.
The seeds are black brown, long oval or inverted oval shaped, slightly flattened, 4.5-5.5 millimeters long, with wings 1.1-1.5 centimeters long; 6-7 cotyledons, 1.3-2.4 cm in length; The primary leaves are strip-shaped, measuring 1.8-2.4 centimeters in length, with grooves on top and dense fine serrations on the edges. The leaf surface also has sparse tooth hairs. The flowering period is from May to June, and the cones mature from September to October of the following year.
The shape of the female cone flowers and cone scales, the color of the small branches, and the texture of the needle needles of Pinus sylvestris var. mongolica are similar to those of Pinus densiflora in Europe. However, the bark at the lower part of the old tree trunk is thicker, deeply longitudinally split, gray brown or black brown, and the upper bark is yellow to brown yellow, splitting into thin pieces and falling off; The length of needle needles varies greatly, reaching up to 12 centimeters in length and 1.5-2 millimeters in diameter. The winter buds are light brown yellow and other morphological characteristics are different from those of European red pine. The tree shape of Pinus sylvestris var. mongolica varies depending on the growing environment: trees grown in the mountainous areas of the Greater Khingan Range have a pointed tower shaped crown and straight, tall trunk ends; Trees born in the sand dune areas west and south of Hailar have a flat crown and shorter trunks. Further research is needed to determine whether these two types need to be classified.