Bidens pilosa
Family
Compositae
Synonyms
Bidens sundaica Blume, Bidens leucorrhiza (Lour.) DC., Bidens pitoga L. var. minor (Blume) Sherff.
Vernacular Names
| Malaysia | Kancing baju, pall-pall pasir, keroten. |
| English | Black jack. |
| Indonesia | Ajeran, hareuga (Sundanese), jaringan, ketul (Javanese). |
| Papua New Guinea | Ivu na mag (Gunantuna, New Britain), rakot (Kurtatchi, Bougainville). |
| Philippines | Dadayem (lbanag), burburtak (Ilocano), pisau-pisau (Bisaya). |
| Thailand | Puen noksai. (northern), kee nok sai, yaa koncham khaao (central). |
| Vietnam | D[ow]n bu[oos]t, t[uwr] t[oo] hoang, q[ur]y tr[aa]m th[ar]o. |
| French | Sornet. |
Geographical Distributions
B. pilosa originates from tropical America but is now distributed and naturalised as a weed in most tropical and subtropical regions of the world, even sometimes extending into some temperate areas. In South-East Asia it is common in many places, except in Kalimantan and the Moluccas.
Description
This is an annual and erect herb that is up to 1(-2) m tall. Its stem is 4-angled, hairless or sparsely hairy. The leaves are arranged opposite, pinnately 3-5-lobed and the lower and/or upper leaves are occasionally simple, up to 15(-20) cm long. They are hairless or sparsely hairy on both surfaces. The margin is usually serrate or crenate-serrate while the segments are egg-shaped to lance-shaped. The first apex terminal with a stalk is the largest. The 5-12 mm flower head is solitary or in lax paniculate cymes. The cyme usually radiates. The outer ring of flower stalk consists of 7-10 petals size 3-4 mm x 0.5-0.8 mm and they are spoon-shaped, abruptly bent during pollination. The inner petals are egg-shaped-lance-shaped with ray flowers absent or 4-8 but sterile. The petal is 7-15 mm long, white to yellow or pinkish while the disk flowers are 3.5-5 mm long. The fruit is linear with 4-6 ribbed. The fruit size is between 4-13 mm long with 2-3(-5) 2-4 mm long retrorsely barbed bristles. (1)
Ecology / Cultivation
B. pilosa is a very common weed of sunny, often disturbed places like roadsides, fields, thickets and along water-courses, up to 2500 m altitude.
Line Drawing / Photograph
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References
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View Abstract: Plant Resources of South-East Asia No 12(1). 1998, .
