Helicteres isora L.
Family
Sterculiaceae
Synonyms
Helicteres grewiaefolia DC., Helicteres roxburghii G. Don, Helicteres chrysocalyx Miq. ex Mast.
Vernacular Names
| Malaysia | Chabai tali, chabai lintal, kayu ulas. |
| English |
Red isora, Indian screw tree. |
| Indonesia | Jelumpang, dlumpangan (Javanese), puteran (Sundanese). |
| Myanmar | Thoo-gnaichay. |
| Thailand |
Po pit (central, northern), cho (Karen, Chiang Mai), po thap (Chiang Mai). |
| Vietnam | Du[oo]i ch[oo]n. |
Geographical Distributions
Helicteres isora is distributed from India, Pakistan, Nepal and Sri Lanka through Burma (Myanmar), Thailand, Indo-China, Malaysia and Indonesia to southern China and northern Australia. It is occasionally grown in Java.
Description
Helicteres isora is a shrub or small tree that can grow up to 2-4(-8) m tall. Its bark is finely wrinkled, lenticellate and pale. All young parts are often densely clothed with long, yellowish and stellate hairs.
The leaves are simple and arranged in two vertical rows. The stipules are slender, measure 3-10 mm long and caducous. The petiole is up to 4 cm long. The blade is rounded to obovate, measuring 5-21 cm x 3-18 cm, and with rounded to subcordate base but sometimes oblique. The margins are irregularly serrate, with rounded to acuminate apex, palmately 3-5-veined and sometimes slightly lobed near the apex. They are variably covered with simple and stellate hairs, often densely on the underside.
The inflorescence is an axillary fascicle of usually 2( -5)-flowered cymes with small, sessile and basal glands. The peduncle is 2-5 mm long, and with linear bracts 3-5 mm long. The flowers are bisexual, irregular, about 2.5 cm in diametre and fragrant. The pedicel is up to 1 cm long. The bracteoles are linear. The sepal is 1-2 cm long, tubular, yellow, and with 5 triangular and unequal lobes. The 2 inferior lobes are connate almost to the apex while the 3 superior lobes are separated. There are 5 petals which are unequal, clawed, 3-4 cm long and bluish at anthesis but turn bright red. The 2 broader lower petals measuring about 3 cm x 1.5 cm with a short claw is winged or widened towards the apex while the 3 upper petals are narrower, measuring about 1 cm x 0.5 cm, and with a claw up to 2.5 cm long which is auricled near the apex.
The gynandrophore is 3-6 cm long with red apical glands. The staminal tube is 2.5 mm long, making an angle of 90° with gynandrophore, terminated by 10 stamens (filaments connate in lower 2/3) and, more inwardly inserted and often hidden by the stamens. There are 5 staminodes altogether. The filaments are short, and with 2-celled anther which are parallel to each other. The pistil is with a 5-celled, red-glandular ovary, and 5 subconnate short styles.
The fruit which is 4-8 cm long consists of 5 twisted follicles. Each follicle is about 20-25-seeded. The seed is angular-subrhomboid, measuring about 2.5 mm x 1.5 mm x 2.7 mm, finely warty, smooth and dark brown.
Ecology / Cultivation
Helicteres isora is a gregarious species common in evergreen forests and secondary jungles along roads and forest edges. In Java, H. isora is found in relatively dry areas up to 300 m altitude, the habitats including teak forests, brushwoods and roadsides. In Thailand, it is found in deciduous forests and scrub areas. Fertile soils rich in humus are preferred; in sandy and lateritic soils, the plants are stunted, much branched, and with a very thin bark. In Hainan (China), H. isora is a common weed in sown pastures.
Line Drawing / Photograph
References
- Plant Resources of South-East Asia No.17: Fibre plants.
