l by Dr. Lalith Gunasekera
(December 14, Melbourne, Sri Lanka Guardian) My recent visit to Sri Lankan hill country provided me with great pleasure as well as heart breaking experience as I recognised large amount of invaders within this beautiful mountains of hill country. Gal Goraka or Gal Idda botanically named as CULSIA ROSEA is widely grown as an ornamental in tropical regions of the world. It was introduced to Sri Lanka in 1866 via Royal Botanic Gardens at Peradeniya during the British ruling era. My recent visit to Central mountain regions in Upcountry found that this species is being invaded in several naturally beautiful areas such as Laksapana, Norton area, Nawalapitia, Ulapane, Yatiyantota, Ruwanwella, Bulathkohupitiya.
Gal goraka plant has been invading roadsides, along water ways, wetlands, hilly mountains, rocky areas. It has formed dense stands over small areas and is still spreading. They invade and compete with endemic grasses, herbs for nutrients, water, light and space. Dense infestation of gal goraka completely smothered important food sources such as small herbs, shrubs and native grasses used by native animals.
Gal goraka originated in tropical West Indies and Mexico region. The wide spreading, densely foliated, rounded 5-10 m tall evergreen tree has a short trunk and broad, thickened dark green leathery leaves. Leaves can be written on with a fingernail. That is why some people named this plant as “Autograph tree”. The plant is often beginning as an epiphyte (the plant that grows upon another plant) on other trees and forming hanging aerial roots. Though it does rely on a large tree for support, this species does not seem to pose a major threat to its host – rarely growing large or high enough to compete with it for sunlight.
Features of the plant
• Leaves simple, opposite, 8-20 cm long.
• Waxy leaves are used by the plant to store water. Each leaf is very widely rounded in shape.
• The disk shaped flowers are large (10 cm diameter), attractive and showy. Seven fleshy snow white petals surround a button sized green central pistil.
• Flowers solitary terminal or in the axils, open facing downwards in the late afternoon or evening are probably bat pollinated.
Gal goraka flower, leaves
• Fruits begin to grow immediately and they mature five months later as glossy green poisonous capsules (5-7 cm in diameter).
• These fruits turn black when ripe and split open into a flower like star. This unique shaped fruit is sometimes used in flower arrangements.
• Inside of the fruit, eight narrow compartments hold many small orange ariled white seeds.
• Seeds are very attractive to birds and other wildlife and they germinate readily in the landscape and surrounding areas. Some of the seed will end up high in the branches of other trees and can germinate in the crotch, sending down aerial roots.
• Propagation is by seeds, cuttings or air layers.
• Gal goraka trees are extremely hardy grow well in both wet and dry sites.
• An experiment in USA has discovered that Gal goraka plants exhibit Crasulacean Acid Metabolism (CAM), a photosynthetic mechanism which aids in conserving moisture. This type of mechanism is also used by Katu Pathok (Cactus plants).
Gal goraka invasion in upcountry hill area
• This plant can be found anywhere sunlight and rainfall are abundant.
• Gal goraka plants can produce large communities and replace all other native plants and prevent their seedling growth.
Gal goraka areal roots covering a stone
Central mountain region of Sri Lanka is ideal place to growth and development of gal goraka plants. Now it is spreading out of hand especially in beautiful areas in upcountry. It will be affected the eco-tourism of the country as it covers beautiful rocky areas in landscape, smother and displace native flora and fauna. Relevant authorities should make suitable actions sooner rather than later to prevent our unique environment from alien plant invasions.