''Dipterocarpus bourdillonii'' is a species of large tree in the family

Dipterocarpaceae Dipterocarpaceae is a family of 16 genera and about 695 known species of mainly tropical lowland rainforest trees. The family name, from the type genus ''Dipterocarpus'', is derived from Greek (''di'' = two, ''pteron'' = wing and ''karpos'' = fru ...

endemic to the Western Ghats principally in the state of

Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

. It is a Critically Endangered species according to the ''

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

''. It is a characteristic tree of the low-elevation tropical wet evergreen rainforests in the Western Ghats.

Description

Tall, evergreen trees, up to 49 m tall, with grey bark that flakes off irregularly in mature trees. The tree trunk develops as a straight bole, and may develop buttresses at the base, forming a dome-like canopy at the top. The young parts such as shoot tip and leaf buds are covered with dense brownish hairs. The leaves are simple, alternate, with large

stipules In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

that drop off, leaving an annular scar. The leaf petiole is 4-5.5 cm long, swollen at the apex, and

tomentose Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant ...

. The leaves are large, about 18-45 cm long by 12-25 cm broad. The leaf blade is ovate or obovate in shape, thick, with stellate hairs on the lower surface and glabrous or with sparse, silky hairs on the upper surface. There are 13-23 pairs of lateral veins that are parallel and raised on the lower surface. The leaf base is rounded or subcordate tapering gradually or abruptly to a pointed tip. The flowers are bisexual, in axillary

racemes A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

of three to five flowers, each about 10 cm long. The flowers have five calyx segments, of which two are elongated into wings, while the other three are shorter and triangular. The sepals of the calyx are green and red-tinged, especially the two that elongate into the wings of the fruit. The calyx tube is distinctly ribbed. The flowers are about 3.5 to 5 cm long, with pinkish and white petals. The flowers have about 30 stamens; the superior ovary is 3-loculed, with two ovules per locule, with a finely cylindrical style that has silky hairs on lower half. The fruit is a

nut Nut often refers to: * Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds * Nut (hardware), fastener used with a bolt Nut or Nuts may also refer to: Arts, entertainment, and media Co ...

, about 2 cm in diameter attached to thickened, accrescent calyx lobes. The calyx tube is about 3.5 cm in diameter, 5 winged, with two elongated, wing-like calyx segments about 10 long by 2 cm wide.

Taxonomy

The species was described by

Dietrich Brandis Sir Dietrich Brandis (31 March 1824 – 28 May 1907) was a German-British botanist and forestry academic and administrator, who worked with the British Imperial Forestry Service in colonial India for nearly 30 years. He joined the British civil ...

, after the forester

T. F. Bourdillon Thomas Fulton Bourdillon (1 May 1849, Madras – 19 December 1930, Bexhill-on-Sea) was a British-Indian botanist, who worked as a Conservator of Forests in the princely state of Travancore. He came to Travancore (at present Southern Kerala) as ...

. It co-occurs in the Western Ghats with ''

Dipterocarpus indicus ''Dipterocarpus indicus'' is a species of large tree in the family Dipterocarpaceae endemic to the Western Ghats of India. It is recognised as an endangered species An endangered species is a species that is very likely to become extinc ...

'', from which it differs in having a hairy shoot apex and ribbed calyx tube (glabrous shoot apex and smooth calyx tube in ''D. indicus'').

Common Names

The species is known by a number of names in local languages:

Kannada Kannada (; ಕನ್ನಡ, ), originally romanised Canarese, is a Dravidian language spoken predominantly by the people of Karnataka in southwestern India, with minorities in all neighbouring states. It has around 47 million native s ...

: Dhuma;

Malayalam Malayalam (; , ) is a Dravidian language spoken in the Indian state of Kerala and the union territories of Lakshadweep and Puducherry (Mahé district) by the Malayali people. It is one of 22 scheduled languages of India. Malayalam was des ...

: Chiratta-anjili, Kalpayin, Karanjili;

Tamil Tamil may refer to: * Tamils, an ethnic group native to India and some other parts of Asia ** Sri Lankan Tamils, Tamil people native to Sri Lanka also called ilankai tamils **Tamil Malaysians, Tamil people native to Malaysia * Tamil language, nati ...

: Karanjili; Kadar: Aeralan

Distribution and status

''Dipterocarpus bourdillonii'' is endemic to the Western Ghats. It is reported to occur in low-elevation tropical wet evergreen rainforest along river courses at elevations between 175 m and 650 m above sea level.Swarupanandan, K., Indira, E.P., Muralidharan, E.M., Pandalai, R.C., Jose, P.A., & Sanjappa, M. 2013. ''Species recovery of Dipterocarpus bourdillonii and Humboldtia bourdillonii, two critically endangered endemic trees of Western Ghats''. KFRI Research Report No. 463, Kerala Forest Research Institute, Peechi, Thrissur, 86 pages. The species is distributed across some 23 locations, mainly in Kerala and southern Karnataka. In

Kodagu district Kodagu (also known by its former name Coorg) is an administrative district in the Karnataka state of India. Before 1956, it was an administratively separate Coorg State, at which point it was merged into an enlarged Mysore State. It occupies ...

Karnataka Karnataka (; ISO: , , also known as Karunāḍu) is a state in the southwestern region of India. It was formed on 1 November 1956, with the passage of the States Reorganisation Act. Originally known as Mysore State , it was renamed ''Karnat ...

a study reported only 14 individuals of the species in three patches. Some of the known locations of the species include in

: Kodagu and Mari Gunty; and in

Aralam Wildlife Sanctuary Aralam Wildlife Sanctuary is the northernmost wildlife sanctuary of Kerala, southwest India. It is in area and located on the western slope of the Western Ghats. It was established in 1984. The headquarters of the sanctuary is near Iritty ...

: Chavachi thodu; Attappadi: Chittoor River; Mannarkkad: Meenvallam; Urulamthanni: Pinavurkudi; Pooyamkutty: Manikandanchal; Muzhiyar: Moonnumukku; Periyar Tiger Reserve: Pampa; and Achenkoil: Vazhaperiyar, Kallar valley. In 2021-22, a population of at least 40 mature individuals was recorded in the

Anamalai Tiger Reserve Anaimalai Tiger Reserve, earlier known as Indira Gandhi Wildlife Sanctuary and National Park and as Anaimalai Wildlife Sanctuary, is a protected area in the Anaimalai Hills of Pollachi and Valparai taluks of Coimbatore District and Udumalaipetta ...

, Tamil Nadu. According to the ''IUCN Red List'', the global population is estimated to number less than 250 mature individuals, and no sub-population has over 50 individuals. This species is estimated to have an extent of occurrence of 27,803 km² and a relatively small area of occupancy (96 km², and unlikely to exceed 500 km²). As a result the species is classified as Critically Endangered.

Breeding system and dispersal

Studies on the reproductive biology, pollination, and dispersal of the species carried out in Kerala have yielded insights into the breeding system. The species is reported to flower between mid-November to late-December, with the fruits maturing by May. The inflorescence originates from leaf axils as clusters of 5-7 flowers arranged alternately, and they mature to produce flowers in 14–16 days. The trees remain flowering for about 14-20 days, with one flower in each inflorescence opening on alternate days, or rarely on consecutive days or the same day. The flowers begin to open at dusk around 6:45 p.m. and are fully open around 7:15 p.m, by which time, the flower has viable pollen grains and receptive stigma. While about 95% of the pollen grains become non-viable by 24 hours, the stigma remains receptive even 20 hours after flower opening.

Pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...

is carried out mainly by

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

, chiefly two species of honey bees, ''

Apis cerana indica ''Apis cerana indica'', the Indian honey bee, is a subspecies of Asiatic honey bee. It is one of the predominant bees found and domesticated in India, Pakistan, Nepal, Myanmar, Bangladesh, Sri Lanka, Thailand and mainland Asia. Relatively non-a ...

'' and ''

Apis dorsata ''Apis dorsata'', the giant honey bee, सिङ्गुस in Nepali, is a honey bee of South and Southeast Asia, found mainly in forested areas such as the Terai of Nepal. They are typically around long. Nests are mainly built in exposed pla ...

'', in Kerala. The latter species visits more flowers and moves longer distances and may be more responsible for

cross-pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, ...

. ''Dipterocarpus bourdillonii'' appears to be self-incompatible and appears to depend on cross-pollination by insects for production of viable fruits. Of the six ovules in each fruit, only one matures into the seed, while the remaining ovules degenerate. After 60-65 days after flower opening, the maturing fruits turn brown and begin to dry on the tree itself. The mature, dry winged fruits are available on the tree about 75-80 days after flower opening. The winged fruits are wind-dispersed just before the

South-west monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...

. Flowering, fruit development, and dispersal are relative synchronous across individuals the population. While the flowers are known to be attacked by

Dipteran Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

and

Lepidopteran Lepidoptera ( ) is an order of insects that includes butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 percent of the total described specie ...

insects, the fruits are attacked by

weevils Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and herbivorous. Approximately 97,000 species of weevils are known. They belong to several families, ...

. Plant propagation studies indicated poor germination (<1%) from seeds sown in soil beds, low to medium survival (12% to 54%) of transplanted wildlings, and risk of attack by a stem boring insect '' Sahyadrassus malabaricus'' (Moore), a moth in the Family Hepialidae, that causes a loss of up to 60% of the planted seedlings. The seedlings attained a mean height of 72 cm (maximum 148 cm) after 2 years.

Conservation

Less then 250 mature individuals of the species exist, in 24 locations along the Western Ghats, with some locations having only 1-5 mature individuals and no location with more than 50 mature individuals. The low population size affects the conservation prospects of the species, besides possibly leading to genetic problems. According to studies carried out in Kerala, ''Dipterocarpus bourdillonii'' shows deficient pollinator populations and degenerating embryos in over 90% of fruits/seeds, suggesting abnormalities in the breeding system, possibly due to inbreeding. However, the moderate survival of transplanted wildlings suggests that this could be used as a strategy for ''in situ'' conservation and restoration of the species.

Gallery

File:Dipterocarpus bourdillonii twig with flower Anamalai Hills 08.jpg, Twig with flower File:Dipterocarpus bourdillonii leaf upperside Anamalai Hills 05.jpg, Leaf upper surface File:Dipterocarpus bourdillonii leaf lower surface Anamalai Hills 06.jpg, Leaf lower surface File:Dipterocarpus bourdillonii dry leaf upper side Anamalai Hills 04.jpg, Dry leaf (upper side) File:Dipterocarpus bourdillonii dry leaf underside Anamalai Hills 03.jpg, Dry leaf (underside) File:Dipterocarpus bourdillonii flowers Anamalai Hills 01.jpg, Flowers, including one cut open File:Dipterocarpus bourdilloni flowers.jpg, Flowers File:Dipterocarpus bourdilloni flower LS.jpg, Flower in section

References

{{Taxonbar, from=Q3029254 bourdilloni Endemic flora of India (region) Flora of Karnataka Flora of Kerala Flora of Tamil Nadu Critically endangered flora of Asia South Western Ghats montane rain forests