Hopea helferi (Dyer) Brandis

"Hopea helferi (Dyer) Brandis is a critically endangered species of plant in the family Dipterocarpaceae. It is found in Cambodia, the Andaman Islands of India, Peninsular Malaysia, Myanmar, VietNam, and Thailand."

Hopea helferi (Dyer) Brandis, J. Linn. Soc., Bot. 31: 62 (1895).

Hopea helferi (Dyer) Brandis; Photo by Hoang Thanh Son

its native range is Indo-China to N. Peninsula Malaysia.

Family:

Dipterocarpaceae Blume

Synonym Name: 

Hopea dealbata Hance

Hopea suavis Kurz. ex Brandis

Shorea helferi (Dyer) Kurz

Vatica helferi Dyer

Vietnamese name:

Sao xanh, Sao lá mía.

Malaysia: 

Giam lintah bukit (general), damar mata kucing, damar siput (Peninsular)

Burma: 

Thingan kyauk

Cambodia: 

Kôki:(r) daèk, phdiek krâhâ:m

Thailand: 

Krabok-krang (general), ngon-kaibok (peninsular), takhian-nuu (eastern)

Describe:

Evergreen trees, about 40 m tall, trunk girth about 3.5 m, buttressed near the base. Bark reddish brown, smooth, at some length also flaked, with white resin, branchlets purplish black, fugaceous tomentose at the tips, shoots, buds buff puberulent. Leaves simple, alternate, elliptic-oblong, about 12-24 x 3.5-8 cm across, base obtuse to cuneate, margins entire, apex obtuse to shallow acuminate, coriaceous, green glabrous above and paler fugaceous tomentose beneath, usually hairy with domatia or gland-like swelling in the axils of the lateral veins, midrib impressed above and prominent beneath, lateral veins 12-16, ascending and obscure above, petiole rugose, slightly canaliculated above, buff puberulent becoming black and glabrous when mature, about 0.5-1.2 cm long, stipules linear, caducous, about 9 mm long, scars inconspicuous. Inflorescence axillary, subterminal or terminal, lax panicles, buff puberulent, about 4-12 flowered, up to 12 cm long. Flowers bisexual, pale yellow or cream coloured, pedicel short, calyx 5 lobed, tubular with very short, imbricate, glabrous, adnate to receptacle, 2 outer longer, ovate-oblong, apex obtuse, thick, tomentose except near the base, 3 inner lobes short, ovate, apex acute or subacuminate, petals 5, imbricate, elliptic-oblong, fleshy, pubescent in exposed portion of the bud. Stamens 15, base connate, 3 appressed with each petal, usually caducous along with the petals, filaments subulate, usually inner ones shorter and sterils, outer ones longer, anthers medifixed, short, connective thin near apex. Ovary tri-locular, cylindric, glabrous or very sparsely puberulous, ovules in two rows, axile placentation, style shorter than the ovary. Fruit large, nutlike, globose-ovoid, about 1.2-1.5 cm across, enclosed in calyx tube with 2 accrescent lobes like wings, longer lobes about 6.5 x 1.8 cm across, longitudinal veins 7-9, joined by cross veins, shorter 3 lobes, ovate, apex obtuse, puberulous outside, about 5 x 3 mm across.

Distribution: 

Andaman Is., Cambodia, Laos, Malaya, Myanmar, Thailand, Vietnam (Dong Nai Cultural Nature Reserve).

Ecological:

It is found in lowland and hill forest from sea-level up to 1000 m altitude. It occurs as a main canopy or understorey, rarely as an emergent tree in evergreen or seasonal, semi-evergreen forest. The semi-evergreen forest accommodates the majority of the species, often narrow endemics. The different species occur in a wide variety of forest types ranging from mixed dipterocarp forest to heath forest and mixed peat-swamp forest and, consequently, on a wide variety of soil types, including limestone. Some species occur markedly gregariously with comparatively large gaps between the groups.. 

Flower times:

The tree started to flower in April to July .

Type:

Helfer [s.n.], Myanmar K000700745 Unknown type material

Uses:

It is a valuable source of construction timber, especially for boat construction. The tree yields a resin which is used locally.

Diseases:

Hopea species are susceptible to various insect pests, virus and fungi, affecting leaves, fruits and roots.

References:

https://www.ipni.org/n/320910-1

http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:320910-1

https://en.wikipedia.org/wiki/Hopea_helferitracuuduoclieu.vn

https://www.frim.gov.my/colour-of-frim/hopea-helferi-flowers-of-a-decade/wppaspec/oc1/cv0/ab15/pt59

https://uses.plantnet-project.org/en/Hopea_helferi_(PROSEA)

https://indiabiodiversity.org/species/show/227374