SRALAO/THAO LAO
The species is native to the deciduous and semi-deciduous forests of Cambodia, Laos, Thailand and Vietnam where often is one of the dominant species, at low altitudes.
The genus was dedicated by Linnaeus to his friend, Magnus Lagerström (1691-1759) who was director of the Swedish East India Company; the specific name is the Latin adjective “calyculatus, a, um” = provided of calyculus (epicalyx), bracts placed immediately under the calyx. Common names: queen’s flower (English); sralao (Khmer); puay, puuay (Lao); mai ta bek, ta baek (Thai); bằng lăng ổi, sang lẻ, thao lao (Vietnamese).
The Lagerstroemia calyculata Kurz (1872) is an evergreen or semi-deciduous tree, up to about 25 m tall, with trunk, up to 50 cm of diameter, irregularly waved, with grey-brown bark tending to flake.
The leaves, on a 0,5-1 cm long petiole, are opposite, simple, oblong with pointed apex and entire margin, 8-18 cm long and 3-5 cm broad, glabrous above, pubescent below. Terminal panicle tomentose inflorescences, 10-20 cm long, carrying numerous hermaphroditic sessile or sub-sessile flowers with campanulated calyx, about 0,5 cm long and covered by yellowish tomentum, with 6 triangular lobes having pointed apex. Corolla with 6 unguiculate petals (petals with long narrow base similar to a stem) with obovate edge with wavy margins, white or pale violet, 0,5-0,8 cm long and numerous stamina.
The fruits are blackish oblong capsules, 0,7-1,2 cm long and 0,6 cm of diameter, with persistent calyx, usually containing 6 dark brown seeds. It reproduces by seed, in organic loam maintained humid at the temperature of 24-26 °C, and by cutting.
Species of easy cultivation and slow growth utilized, in particular in the origin countries, also as ornamental plant in parks and gardens and as road tree, cultivable exclusively in the tropical and subtropical climate zones, not bearing temperatures around the 0 °C, if not exceptional and of short duration and with serious damage to the aerial part. It requires an exposition in full sun or partially shaded and is not particular about the soil, provided draining, preferably acidic.
The wood, of average quality, hard and heavy, but not very weather resistant, is utilized in the civil constructions, for floors, partition walls and internal parts in general, in the naval furnishing, for furniture, agricultural tools, handicrafts and locally as fuel. The bark, rich of tannins, alkaloids, flavonoids and other bioactive compounds, is utilized in the traditional medicine for various pathologies.
LAGERSTROEMIA
Lagerstroemia calyculata Kurz.
Lagerstroemia angustifolia Pierre
Family: Lythraceae Horoscope
Set: Sim Myrtales
Guava Crape Myrtle
Describe:
Deciduous tree 30 - 35m high, 40 - 80cm diameter. The skin is light yellow, interspersed with very smooth greenish brown pieces, the flesh is light yellow and fibrous. Branches are thin and have yellow hair. Leaves are oblong lanceolate, obtuse base, slightly deviated, apex elongated into segments, 7 - 14cm long, 2 - 5cm wide. Side veins 10 - 13 pairs, hairy. Leaf stalks are 3 - 5mm long, hairy.
Inflorescences are panicle-shaped, have many yellow hairs, 12 - 20cm long. The sepals are bell-shaped and have many star-shaped feathers, with 6 triangular lobes on them. Petals 6, round or inverted heart-shaped, 2.5mm wide. Stamens are many, nearly equal. Gourd 5 - 6 cells, hairy at the top, long proboscis; The capsule is ovoid, 12mm long, 1/3 submerged in the calyx, cracked into 6 pieces. Seeds are 8mm long.
Distribution:
World: Laos, Cambodia...
Vietnam: the tree grows in Quang Binh, Quang Tri, Thua Thien, Gia Lai, Kontum, Dak Lak, Lam Dong and many Southern provinces.
Ecological:
The plant prefers deep, thick soil with average moisture. Regeneration by seeds and shoots is good. Growth rate is slow. Flowers June - July. Fruits March - April next year.
Uses:
The wood has a distinct sapwood core, white sapwood, gray-yellow or brown core, hard and heavy. Density 0.71 - 0.90, annual rings are difficult to see, rays are very small, density is very high. Wood is less durable if left outdoors, easy to saw but difficult to process.
Referenced documents : Economic wood trees - Tran Hop, Nguyen Boi Quynh - page 481.