In this article we will discuss about:- 1. Characters of Dipterocarpaceae 2. Distribution of Dipterocarpaceae 3. Economic Importance 4. Affinities.
Characters of Dipterocarpaceae:
Gigantic trees with an abundant resin; coracious leaves; flower actionomorphic, hermaphrodite, hypogynous; sepals 5, polysepalous, persistent; petals 5, polypetalous; stamens many in one to several whorls, slightly polyandrous, carpels 3, syncarpous, superior; Fruit samara enclosed in persistent sepals.
A. Vegetative characters:
Habit:
Gigantic trees rarely shrubs.
Root:
Tap, branched, deep.
Stem:
Erect, high, woody, few branches, with resin ducts.
Leaf:
Simple, entire, coracious, stipulate, stipules small sometimes surrounding the internode.
B. Floral characters:
Inflorescence:
Paniculate terminal or axillary spikes or racemes.
Flowers:
Actinomrphic, hermaphrodite, hypogynous, pentamerous; flower axis broad. Saucer shaped or concave sometimes; complete.
Calyx:
Sepals 5, unequal, polysepalons persistent and wing-like in fruit (Shorea), imbricate or valvate.
Corolla:
Petals 5, polypetalous, imbrilate contorted or much imbricate.
Androecium:
Stamens 5 to 15 or indefinite, in one to several whorls; filaments short usually, rarely long, anther lobes unequal, connective produced at the apex very often.
Gynoecium:
Carpels 3 usually, syncarpous, superior, trilocular, axile placentation, ovules 2 in each locule; stigma always exceeds the stamens.
Fruit:
Leathery, woody, indehiscent, surrounded by persistent winged calyx segments.
Seed:
Non-endospermic.
Pollination:
Entomophilous sweet scented flowers.
Floral formula:
Distribution of Dipterocarpaceae:
The family comprises 25 genera and 350 species. It is mainly confined to the tropics of old world, Malasia, Philippines. In India Shorea robusta (sal) is distributed in Assam, Terai, Central provinces, Bihar and forming extensive sal forest. Monoporandra is endemic to Ceylon.
Economic Importance of Dipterocarpaceae:
The plants of Dipterocarpaceae are of great value for resins and timber, oils, camphor and turpentine.
1. Food:
The starchy seeds of Vateria acuminata, Vatica and Doona are used as food.
The seeds of Shorea robusta produce ‘sal butter’ which is used as an adulterant for ghee and instead of Cocoa butter in the manufacture of Chocolates.
The seeds of Vateria indica produce vegetable butter, ‘Malabur tallow’ or vateria fat or ‘pincy tallow’ which is used in confectionary and as a substitute for ghee and its bark is in demand in the manufacture of arak and jaggery.
2. Timber:
Timber is obtained from Shorea robusta (sal). It is valuable timber for house building, gun carriage manufacture, ships, railway sleepers etc. it is durable under water and is white-ants proof.
Hopea parviflora yields excellent timber which is particularly useful in pile and bridge construction.
The timber of Dipterocarpus turbinatus is used for boat-building and structural work.
3. Resin & turpentine:
Shorea koordarsis yield turpentine and dumar resin called ‘dhoona’ and is as incense. The stems of Dipterocarpus turbinatus are exploited for ‘garjan oil’, a balsam or resin, which is useful in making varnishes and lithographic inks. ‘Chooa’ a dark strong-smelling thick balsam is obtained from Isauxis, lanceaefolia.
Hopea micrantha produces the valuable dammar called ‘mata Kuching’. Yellow camphor, the ‘Borneo camphor’ or ‘Sumatra camphor’ is obtained from Dryobalanops aromatica, from it (D. aromatica) resins, oils, turpentine etc., are also obtained.
The oleoresin obtained from the trunk of Vateria indica is ‘piney varnish’ when soft and ‘Indian copal’ or ‘Copal varnish’ when hard.
Affinities of Dipterocarpaceae:
The Dipterocarpaceae shows resemblance with Guttiferae and Theaceae but can be distinguished by the enlarged persistent calyx, resin ducts and stipulate leaves.
Bentham & Hooker included the genera Ancistrocladus and Luphira in Dipterocarpaceae, but E. Gilg transfered them to the families Ancistrocladaceae and Ochnaceae, respectively. Hence, the Dipterocarpaceae has relationship with the families. Gilg estabilished relationship of Diptero- carpaceare with Tiliaceae.
Dipterocarpaceae resembles with the Magnoliaceae in the possession of large stipules but differs from it in the presence of persistent calyx.
Common plants of the family:
Dipterocarpus turbinatus – Garjan balsam – A huge tree.
Hopea odorata – A tall garden ornamental plant.
Shorea robusta – Sal tree of India.
Vateria indica – Yields edible seeds.
Division of the family and chief genera:
Tribe I. Dipterocarpoideae:
Anthers basifixed, filaments short. Resin and balsam ducts are present in the pith.
Subtribe (a) Dipterocarpeae:
Calyx pitcher shaped, enclosing the fruit, the apices of the calyx tube enlarging into long wings. Stamens more than 20. Style on large stylopodium. Genera: Dipterocarpus, Anisoptera etc.
Subtribe (b) Dryobalanopsieae:
Lower portion of fruit sunk in cupular calyx tube. Stamens numerous, connective shortly appendaged. Stylopodium (disc-like swollen enlargement at the base of the style) is absent. Fruit three valved. Genus: Dryobalanops.
Subtribe (c) Shoreae:
Calyx wings unequal; calyx lobes imbricate. Stamens 10-15 or many somtimes, connective appendage very long. Genus : Shorea.
Subtribe (d) Vaticeae:
Calyx lobes valvate, calyx wings equal and short, usually 2 in number. Stamens 15 generally, rarely 10, anther appendage short, blunt. Stylopodium absent. Genus: Vatica.
Subtribe (e) Vateriae:
Calyx lobes imbricate, apices of calyx lobes equal, shorter than fruit. Stamens 5 to numerous, filaments short or absent, anthers linear long. Stylopodium absent. Genus: Vateria.
Tribe II. Monotoidaeae:
Anthers more or less versatile, filaments of stamens long. Resin ducts and balsam sacs are absent in the pith. Genus: Monotes.