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  Bombax insigne Wall.
Vernacular name  Kallelavu, Mullilavu (Malayalam); Kalilavu, Seem-poolai, Kattu elavam (Tamil); Semul (Hindi) (Chacko et al., 2002).
Common name  Semul (Chacko et al., 2002), Silk cotton tree (Bose et al., 1998).
Synonyms  Salmalia insignis (Wall.) Schott & Endl. (Sasidharan, 2004; Chacko et al., 2002; Bose et al., 1998).
Family  Bombacaceae
Subfamily 
Origin 
Distribution  Occurs in the forests of Western Ghats from North Kanara Southwards through Konkan and Anamalai hills to Kerala. It also extends to the Deccan districts. It is rarely common in the Andamans, Bangladesh, Myanmar and Malay Peninsula (FRI, 1981 from Chacko et al., 2002).
Description  Fast growing, large prickly deciduous tree attaining a height of 30 m and a breast height diameter of 159 cm (FRI, 1981 from Chacko et al., 2002).
Flowering season  December and continues up to February.
Fruiting season  Fruits mature in March.
Flowers  Flowers 10 to 15 cm long, solitary, calyx 3 cm long, silky inside; petals red; stamens numerous, filaments, united into 4 or 5 bundles (Bose et al., 1998), scarlet or white, scattered on leafless branches.
Fruits  Fruit is a capsule up to 25 cm long and 5 cm in diameter (Bose et al., 1998) oblong, 5-angled, tomentose.
Fruit type  Capsule.
Seeds  Seeds many, obovoid, dark brown coloured seed enveloped in dense silky floss (Chacko et al.,2002).
Seed length  0.9 cm (Chacko et al., 2002).
Seed width  0.5 cm (Chacko et al., 2002).
Seed thickness 
Seed weight  11,640 to 20,110 seeds/kg (Sen Gupta, 1937; FRI, 1981 from Chacko et al., 2002).
Seed dispersal  Wind dispersal, Bees.
Seed Collection  Ripe capsules are collected from the tree well before they begin to dehisce (Chacko et al., 2002).
Transportation of seeds  Capsules collected in cotton / polythene bags are packed and transported, and no special care is suggested during transport (Chacko et al., 2002).
Seed processing  Capsules are spread out in the sun on a mat to dry and split open. The floss is separated from the seeds by churning with a bamboo stick (FRI, 1981 from Chacko et al., 2002).
Seed storage  Recalcitrant (CABI, 1998). Seeds can be stored in a gunny bag after drying in the sun (FRI, 1981 from Chacko et al., 2002).
Viability period  Seeds are viable for about one month under ambient room temperature (Chacko et al., 2002).
Seed emptiness  No information (Chacko et al., 2002).
Seed pre treatment  Soak the trees in cold water for about 12 hrs (FRI, 1981 from Chacko et al., 2002).
Germination type  Epigeal (FRI, 1981 from Chacko et al., 2002).
Germination percentage  60 to 90 (FRI, 1981 from Chacko et al., 2002).
Germination period  12 to 21 days (FRI, 1981 from Chacko et al., 2002).
Nursery technique  The pretreated seeds are sown in germination trays containing vermiculite and watered. Seedlings are transplanted to polythene containers filled with potting mixture. Seedlings grow very fast and are used for planting in the same year (FRI, 1981 from Chacko et al., 2002).
Method of propagation 
Vegetative propagation 
Pests  Moderate to heavy due to sap sucking by the bug Dysdercus cingulatus Fb. (Heteroptera: Pyrrhocoridae). Nymphs and adults of this insect feed by sucking sap from pods, fruits and seeds (Beeson, 1941 from Chacko et al., 2002).
Diseases  Low (Chacko et al., 2002).
Medicinal properties  Practically everypart of the plant is used by Ayurveda practitioners, but only the gum is recognized by yunani doctors.
Uses  Wood is used in match industry for boxes as well as splints. It also used for packing cases, drum, pencils etc. (Chacko et al., 2002). Fruits yield floss called silk cotton. Tree exudes a gum. The inner bark of the tree yields a good fibre suitable for cordage.
Wood properties  The wood is more durable than that of ordinary semul, and the wood is only slightly discoloured when cut up. Wood structure similar to that of Bombax malabaricum, but pores smaller or more scanty (Gamble, 1922).
References  Get ...
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