Online Manual for the Forest Tree Seeds of Kerala

A Kerala Forest Department Funded Project

Dr. K Sudhakara
Professor & Head of the Department
Dept. of Silviculture & Agroforestry
College of Forestry, Kerala Agricultural University, Thrissur 680 656
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Scientific Name  Sterculia urens Roxb.
Vernacular name  Thondi, Theethondi, Paravakka, Annanvazhukki (Malayalam), Kavalam (Tamil), Kullu (Hindi) (Chacko et al., 2002).
Common name  Karaya
Family  Sterculiaceae
Distribution  It is a native of tropical Himalayas and Southern India. It is found in various areas of central India. Widely distributed over northern, central and peninsular India, usually on stoney or rocky soils; also occurs in Myanmar and Sri Lanka (FRI, 1981). In Kerala, it occurs in moist and dry deciduous forests (Chacko et al., 2002).
Description  A moderate to large sized, deciduous much branched tree reaching a height of 15 m and a breast height diameter of 48 cm. Bole is usually short (FRI, 1981; Chacko et al., 2002; Bourdillon, 1908).
Flowering season  December to January (Bourdillon, 1908).
Fruiting season  April - May (Bourdillon, 1908), May to June (Sen Gupta, 1937; Chacko et al., 2002).
Flowers  Greenish yellow, having unpleasent odour, a few bisexual flowers mixed with large number of male flowers.
Fruits  Follicle long, sessile, coriaceous, spreading, woody 2.5 to 3x2 cm size, oblong, bright red, spreading in a star-like fashion, covered with stiff stining bristles, open on the ventral suture, with seeds attached (Chacko et al.,2002).
Fruit type  Follicle.
Seeds  Seed oblong brown coloured 6 mm long and 3-6 in each follicle (Chacko et al.,2002).
Seed length  6 mm (Chacko et al., 2002).
Seed width 
Seed thickness 
Seed weight  5,291 (Sen Gupta, 1937; Chacko et al., 2002) to 6,360 seeds/kg (FRI, 1981; Chacko et al., 2002).
Seed dispersal 
Seed Collection  Ripe fruits are collected from the tree when they start to dehisce. Seeds can also be collected from the ground soon after fall (Chacko et al., 2002).
Transportation of seeds  Fruits collected in cotton/ plastic/ polythen bags are transported to the processing centre soon after collection (Chacko et al., 2002).
Seed processing  Remove the aril and dry the seed under shade (Chacko et al., 2002).
Seed storage  Recalcitrant (CABI, 1998). Seeds cannot be stored for more than a year (Luna, 1996; Chacko et al., 2002).
Viability period  No information (Chacko et al., 2002).
Seed emptiness  Low (Chacko et al., 2002).
Seed pre treatment  Overnight soaking in ordinary water.
Germination type  No information (Chacko et al., 2002).
Germination percentage  77 (FRI, 1981; Chacko et al., 2002). 88 (sown within few days of collection).
Germination period  7 to 53 days (FRI, 1981; Chacko et al., 2002).
Nursery technique  Seeds are sown in plastic trays containing vermiculite soon after collection and watered regularly. When germination is complete the seedlings are potted in polythene bags of 22.5 x 17.5 cm size filled with potting mixture. After 3 to 4 months of potting, the seedlings reach 15 to 20 cm height (Chacko et al., 2002).
Method of propagation  By seeds or cuttings.
Vegetative propagation 
Pests  Low (Chacko et al., 2002).
Diseases  Moderate (55%). Sixteen fungi and actinomycetes are recorded. Nigrospora sp., Botrytis sp., Phoma sp., Cylindrocladium sp., Pestalotiopsis sp., Fusarium sp., Genicularia sp., Alternaria sp., etc. are the important fungi (Mohanan and Anil Chandran, 2001; Chacko et al., 2002).
Medicinal properties  Gum is polysaccharide in nature and is used in throat infection and in dental fixture powders.
Uses  Bark yields fibre suitable for making ropes. Timber is used for making musical instruments, toys, light packing cases and low-grade pencils. The seeds are edible and are generally eaten after roasting (FRI, 1981; Chacko et al., 2002).
Wood properties  The sapwood is greyish and the heartwood is reddish brown. The wood is moderately heavy with straight grain and coarse texture. Air dry weight is about 545 kg/m3. The wood is very soft, with a light coloured sapwood, and rays of moderate breadth (Bourdillon, 1908). Pores large, often oval and subdivided, very scanty, frequently filled with gum. Medullary rays moderately broad, on a radial section prominent as long, dark, undulating bands, giving the wood a mottled silver-grain; the distance between the rays is larger than the transverse diameter of the pores. Alternate dark and light concentric bands across the rays (Gamble, 1922).
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