Invaders In Knuckles Mountain Range

l by Dr. Lalith Gunasekera

(October 23, Melbourne, Sri Lanka Guardian) Knuckles mountain range is important due to the historical value it carries and therefore it can be categorized as one of the valuable heritages in Sri Lanka. The importance of the knuckles mountain range is obtained from several factors. It has a parasitical quality to it because of the mountain peaks, crystal clear water, cloud forests and exquisite flora and fauna. The remarkable feature of this area is that most of the climatic conditions of Sri Lanka can be found within the extent of a mountain range.

Beautiful knuckle mountains
All these hanging climatic conditions can be experienced within half an hour walks through this valley. In Knuckle mountain range a total of 1033 flowerin plants belonging to 141 families have recorded. Among them 255 are tree species while the balance consists of shrubs and herbs. Considering all these factors, UNESCO has included this area under World Heritage List on 30th of July 2010.
There are two major roads to see the beauty of this mountain range. One road is through Matale – Rattota and Riverston. The other road is via Hunnasgiriya – Meemurray road. I travelled through both roads in August this year and found several emerging invasive plants within the protected areas of this wonderful place. Some of the species are at their early stages of invasion. Thus it would be easy to manage them before they established and invade those important areas and cost massive amount of money and effort to manage them in future.

popcorn csassia
Botanical name: Senna didymobtrya

This cassia species is being spread in knuckle mountain range especially between Hunnasgiriya – Mee-muray roadside and forest areas. The plant originated in Central Africa and usually a several stemmed shrub or tree up to 9 m tall. It is a hairy, aromatic shrub usually growing up to about five meters tall but known to reach nine meters at times. The leaves are up to half a meter long and are made up of many pairs of elongated oval leaflets each up to 6.5 cm long. The plant has a strong scent which has been variously described as being reminiscent of mice, wet dog, peanut butter. The plant flowers plentifully in racemes bright yellow flowers, with some flowers also occurring in leaf axils. The flower raceme has open flowers on the lower part with unopened buds at the tip covered in stark brownish green or black bracts. The flower has five concave petals each 1.5 to nearly 3 centimetres long. The flower has ten stamens, usually seven fertile ones and three sterile staminodes. Some of the stamens have large anthers measuring a centimetre long. The fruit is a flat brown legume pod up to 12 centimetres long which contains up to 16 beanlike seeds up to a centimetre long each.

Popcorn cassia flowers at Knuckles - 2011

Botanical name: Austroeupatorium inulifolium

This is the biggest invader in Knuckles mountain range. Austroeupatorium (suddha) plant is similar appearance to siam weed (Chromolaena odorata) and belongs to the same plant family but grows at higher elevations. It is a neotropical plant widely distributed in its native South America from Panama to Argentina. This plant introduced to Sri Lanka as a flowering plant as well as green manure. This is very aggressive invader and spreading along Knuckle mountain range specially in Riverston area as well as through Hunnasgiriya to Meemuray road. Suddha plant is a perennial spreading shrub grows up to 2.5 m tall. Stems covered with short hairs and moderately branched. Leaves are simple and opposite. The plant produces creamy white flowers.

Suddha plant flowers

Crofton weed, Mexican devil
Botanical name: Ageratina adenophora

Crofton weed is a rapid spreading weed that has become a nuisance in many areas of Sri Lanka. A member of Asteraceae family, crofton weed is a native of Mexico. It is present as a weed in India, Canary Island, Jamica, Hawaii, Fiji, New Zealand, Australia and USA.
Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 m high. Young stems are soft and leaves are bright green trowel shaped, 50-75 mm long, 25 -50 mm wide with the toothed margin.
Flowers are white, in small, dense heads at the ends of the branches. Seeds are slender, angular, 2 mm long, almost black with fine white hairs at the tip. I observed this plant species at Knuckles mountain range near Riverston..

Crofton weed growing in Knuckles

Mist Flower
Botanical name: Ageratina riparia

This is the second biggest invader in Knuckles mountain range. Mist flower plant introduced to Sri Lanka as an ornamental plant, and quickly invades disturbed and open environment. Mist flower is a low growing, sprawling perennial plant 40-60 cm high. It has numerous branching stems which produce roots at the joints when they touch the ground. Leaves are opposite, mostly 7.5 cm long and 2.5 cm wide, toothed along the edges and tapered at each end.
White flowers, similar to crofton weed are produced. The plant prefers a damp, shady environment and in these areas it can impede the growth of native ground cover species and prevent the establishment of many native seedlings. If uncontrolled this aggressive plant can completely dominate native vegetation and modify the composition of native forest and stream side environment.
Mist flower plant has seen in growing along the trail of Horton Plains as well as World’s end. I have clearly seen it along the trail. Further it was heavily infested in knuckles mountains specially along the road to Telecom Tower road in Riverston.
 Mist flower

wild tobacco tree
Botanical name: Solanum mauritianum

The highly invasive environmental weed originated in Argentina. Wild tobacco plant has spread in South Africa, Uganda, USA, Australia, Polynesia and New Zealand.
Plant has oval shaped leaves , upper surface green and sparsely hairy, lower surface grey or fawn, densely hairy. Sharply pointed tips. Flowers numerous in flat topped clusters to about 15 cm diameter at tips of branches. Flower has 5 petals with violet colour. Fruits are berries, round, green turning dull yellow. Large number of seeds are produced by the plant. Seeds spread by water, birds, humans and vehicles,
I have noticed that the plant has been spreading along the road to Knuckles via Riverston and Bambaralla area.
Wild tobacco plant can tolerate shade and moderate drought once established. It can invade grassy woodlands, damp and wet forest, gullies and other moist sites in both disturbed and intact native vegetation, rainforest edges, roadsides and pastures.
Wild tobacco plant grows along the road to Knuckle mountain range.

Yoda Nidikumba
Botanical name: Mimosa pigra

I never expected the next invader in this area. Unfortunately it was Giant mimosa (Yoda Nidikumba). This plant started its journey from Mahaweli river bank and reached to the entry of this mountain range. I have seen several bushes in Panwila and Bambaralla area. This is the time to remove them from this area as soon as possible before it established and ruined this beautiful environment. As you know these plants have round pink flowers and plenty of thrones along the stems.
 Yoda nidikumba in Knuckles region

Time has come to protect knuckles from this kind of alien plant invasions. There should be some field botanist from relevant authorities who should be recognised this new and emerging plant species before they get out of hand.