The Rhododendron arboreum is Nepal's national flower. It is an evergreen shrub or small tree that grows between 1200-3600 meters in altitude and has showy bright red flowers. It was first discovered in 1799 in India and introduced to England in 1811. R. arboreum has oblong-lanceolate leaves and bears up to 20 red, pink, or white flowers in clusters. Its bark, leaves, and flowers contain compounds such as taraxerol, ursolic acid, quercetin, and rutin that have anti-inflammatory and antioxidant properties. Local people use parts of R. arboreum to treat conditions like diarrhea, headaches, and liver disorders.

2. Introduction
 The word rhododendron comes from the Greek words "rhodon",
or rose, and "dendron", or tree. Rhododendron arboreum is the
national flower of Nepal. The Rhododendron arboreum also
known as burans or gurans, belonging to ericaceae. It is an
evergreen shrub or small tree with a showy display of bright red
flowers. Lali Gurans are found at altitudes as low as 1200 meters
and as high as 3,600 meters. Its trees reach a height of up to 15
meters, the tallest in Nepal among other species.

3. History
 The first of many Rhododendron which were to come from
southeastern Asia was the tree species, R. arboreum, with
blood-red flowers, which was discovered by Captain
Hardwicke in 1799 and arrived from India in 1811.
In 1821 Don introduced R. anthopogen and R.
setosum from Asia. In 1823, R. molle, destined to become
famous as one of the parents of the Mollis hybrids, was
introduced from China. In 1832, R. zeylanicum (a
subspecies of R. arboreum) came into England from
Ceylon. From the Himalayan regions of Nepal and sikkim
R. campanulatum was introduced 1825. The native place
are Bhutan, China, India, Nepal and Pakistan.

4. Nomenclature
Kingdom: Plantae
Divison: Angiosperms
Order: Ericales
Family: Ericaceae
Genus: Rhododendron
Species: R.arboreum

5. Common names
 English :rose tree, rhododendron
 Nepali :lali gurans
 Tamil: billu
 Punjabi: adrawal
 Trade name: chalan

6. Habit and habitat
 Altitude: 1200 - 3600 m
 Mean annual temperature: 12 - 17ºC
 Mean annual rainfall: 200 - 1800 mm
 Soil type: The plant prefers light (sandy) and medium
(loamy) soils and requires well-drained soil. The plant
prefers acid soils and can grow in very acid soil. It can
grow in semi-shade (light woodland) or no shade. It
requires moist soil.

7. Macroscopic identification
 Leaves: Leaves glossy green, oblong-lanceolate, 10-20 cm long
and 3.6 cm wide. Crowded towards the ends of branches,
petiole covered with white scales when young.

8. Flower
 The flowers of R. arboreum range in color from a deep scarlet, to
red with white markings, to pink to white. Bearing up to twenty
blossoms in a single truss this rhododendron is a spectacular
sight when in full bloom. Bright red forms of this rhododendron
are generally found at the lower elevations. Calyx- fine cleft,
Corolla-tube spotted funnel shaped, Stamens hypozygnous
declining, Filaments-filiform, Anthers-ovate, Style-capitate.

9. Seeds
 Seeds-minute, dark brown, compressed, thin linear
having an obvolute membrane

10. Fruit
 Fruit a capsule, oblong, curved, longitudinally ribbed,
up to 3.8 cm long and 1.25 cm wide.

11. Stem
 Stem often much branched, crooked or gnarled. Bark
reddish brown, soft and rough, exfoliating in thin
flakes. Stem smooth or rough, sometimes warted;
bark.

12. Microscopic identification
Chromosome number (2n)= 26

13. T.S of leaf

14. ORGANOLEPTIC PROPERTIES
 Appearance: liquid
 Color: Pale yellow
 Aroma: Sweet herbal, faintly balsamic

15. PHYTO-CHEMISTRY
 Bark: The petroleum ether extract of the bark
indicated the presence of a single triterpenoid
substance taraxerol (C30H50O) & ursolic acid acetate
(C32H50O4). The ether extract of the bark following
petroleum ether extract showed the identity of
betulinic acid (C30H48O3). The acetone extract of the
bark gave the substance leuco -pelargonidin
(C15H14O6).

16. Structure
taraxerol
Betulinic acid

17. leaves
 Green leaves contain glucoside,
 ericolin(arbutin) (C12H16O7),
 ursolic acid (C30H48O4),
 α-amyrin (C30H50O),
 epifriedelinol (C30H52O),
 quercetin & hyperoside (C21H20O12)

18. Structure
ursolic acid α-Amyrin epifriedelinol
quercetin

19. Flowers
 Quercetin-3-rhamnoside a crystalline chemical
compound is found the flowers of this species. Three
biologically active phenolic compounds i.e. quercetin
(C15H10O7), rutin (C27H30O16) and coumaric acid
(C9H8O3) are found in flowers of R.arboreum using
high-performance thin-layer chromatography.

20. Pharmacology
 Anti-inflammatory and Anti-nociceptive activity
 Hepatoprotective activity
 Anti-diarrhoeal activity
 Anti-diabetic activity
 Antioxidant or Adaptogenic activity.

21. Medicinal uses
 Rhododendron arboreum’s nectar is brewed to make wine
and is effective in diarrhoea and dysentery.
 Its Corolla is administered in case of fishbone stuck in the
gullet.
 Snuff made from the bark of the tree is excellent cold
reliever.
 The bark juice is used to treat jaundice, diabetes, liver
disorders, and intestinal worms.
 Young leaves can be processed into paste and applied on the
forehead to alleviate headaches.

22. Cont…
 The juice of the flowers is used in the treatment of
menstrual disorders
 Rhododendron is also used in making of aromatic oil,
perfumery and cosmetics.

23. Intoxicating properties
 Rhododendron flower are sweet, sour and are packed
with Vitamin C. However, when too many flowers are
consumed the flower can become intoxicating. Bees
that harvest pollen exclusively from these plants will
often produce honey that is a natural laxative and
hallucinogenic.

24. REFERENCES
 Medicinal plants of india
 A Review-Debjyoti Bhattacharyya
 Nepal's Magnificent Rhododendron
 Agroforestry Database 4.0 (Orwa et al.2009)
 Asian Pacific Journal of Tropical Biomedicine
 A Journal of the Bangladesh Pharmacological Society
(BDPS)

25. Thank you