Senna obtusifolia (L.) H.S.Irwin & Barneby, Fabaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Pacific: High risk, score: 7 (Go to the risk assessment)
Australia:  Reject, score: 14 (Go to the risk assessment)
Risk assessment of Senna obtusa from the Department of Agriculture and Fisheries of Queensland (Australia)

Other Latin names:  Cassia obtusifolia L.

Common name(s): [more details]

English: Chinese senna, coffee weed, habucha, java bean, sicklepod

Japanese: ebisu-gusa

Maori (Cook Islands): pī ‘aungakino

Spanish: dormidera

Habit:  herb

Description:  "Annual or perennial herbs (1-)3-12(-20) dm tall, sometimes somewhat woody toward base, foliage malodorous, roots black with yellow tips.  Leaflets 3 pairs, the distal ones larger, broadly obovate to cuneate-obovate, 1.7-6.5 cm long, 1-4 cm wide, glabrous or pubescent, margins ciliate, apex subtruncate to broadly rounded, apiculate, base with 1 side rounded to cordate, the other cuneate, petiolar nectaries between the lower and occasionally the second pair of leaflets, 1-3 mm long, stipules linear, 3.5-17 mm long, caducous.  Flowers 1-2 in the leaf axils, pedicels filiform at anthesis, greatly thickened in fruit, 7-28 mm long, bracts ovate or lanceolate, 2-5 mm long, deciduous; calyx lobes pale green, inner ones obovate or oblong-obovate, 5.5-9.5 mm long; petals pale yellow, the standard obcordate or cuneate-obcordate, the others oblong-obovate, the longest one 9-15 mm long; filaments of 4 median stamens 1-3 mm long, those of 3 abaxial stamens 1.5-4.5 mm long.  Pods ascending, chartaceous, linear, compressed, 4-angled, usually outwardly curved or sometimes almost straight, attenuate at both ends, 6-18 cm long, 0.2-0.6 cm wide, tardily dehiscent by both sutures, the cavity with well-developed interseminal septa. Seeds brown and glossy, obliquely descending, compressed-rhomboid or irregular, sometimes subcylindrical in narrow fruit, 3.2-6 mm long, crackled with age, the areole 2.5-4.2 mm long"  (Wagner et al., 1999; p. 700).

Habitat/ecology:  "Grassland, forest edges, riparian habitats, floodplains, disturbed sites.  This plant is a significant agricultural weed that also invades natural plant communities.  It grows in desnse thickets, competing for light, water and nutrients and displacing native vegetation.  The species is not nitrogen-fixing due to a lack of nodulation"  (Weber, 2003; p. 400). 

Common as a weed of open disturbed areas, sea level to 1200 feet. In Hawai‘i, "cultivated and naturalized on the Greenwell Ranch, Hawai‘i"  (Wagner et al., 1999; p. 700). Arid lowlands in the Galápagos Islands (McMullen, 1999; p. 198).  In Australia, "disturbed areas such as drainage channels, overgrazed pastures; often in dense swards along rivers and flood plains" (Smith, 2002; pp. 38-39).

Propagation:  "Seed is dispersed in mud adhering to vehicles, machinery, animal hooves and fur or as a contaminant of hay, fodder and pasture seed.  Seeds may be eaten by stock with mature seed germinating in the dung." (Smith, 2002; pp. 38-39).

Native range:  Probably neotropics. Widely cultivated for medicinal uses and naturalized. Used by the Japanese for tea. (Wagner et al., 1999; p. 700).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Sierra Negra, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santiago Group	Santiago Island	introduced invasive	Charles Darwin Foundation (2008)
Federated States of Micronesia Chuuk Islands	Chuuk Islands	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 98)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 98)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced invasive	Herrera, Katherine/Lorence, David H./Flynn, Timothy/Balick, Michael J. (2010) (p. 96) Naturalized
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		Bishop Museum (Honolulu) (1949) (voucher ID: BISH 153634) Taxon name on voucher: Senna tora (L.) Roxb.
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 98)
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) As Senna tora (Linnaeus) Roxburgh. Voucher cited: J. Florence 8476 (PAP) Adventice
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island		Bishop Museum (Honolulu) (1987) (voucher ID: BISH 540429) Taxon name on voucher: Senna tora (L.) Roxb.
French Polynesia Society Islands	Raiatea (Havai) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) As Cassia tora L. Voucher cited: J. Florence 3701 (PAP) Adventice
French Polynesia Society Islands	Raiatea (Havai) Island		Bishop Museum (Honolulu) (1982) (voucher ID: BISH 491156) Taxon name on voucher: Cassia tora L.
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) As Cassia tora L. Voucher cited: J. Florence 2503 (PAP) Mauvaise herbe des cultures et le long des chemins.
French Polynesia Society Islands	Tahiti Island		Bishop Museum (Honolulu) (1982) (voucher ID: BISH 492812) Taxon name on voucher: Cassia tora L.
French Polynesia Society Islands	Tahiti Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1981) (voucher ID: PTBG 37282) Taxon name on voucher: Senna tora (L.) Roxb.
French Polynesia Tuamotu Archipelago	Hao (Hau) Atoll	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Adventice
French Polynesia Tuamotu Archipelago	Makatea (Ma‘atea) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) As Senna tora (Linnaeus) Roxburgh. Voucher cited: J. Florence 9049 (PAP) Adventice
French Polynesia Tuamotu Archipelago	Makatea (Ma‘atea) Island		Bishop Museum (Honolulu) (1988) (voucher ID: BISH 560418) Taxon name on voucher: Senna tora (L.) Roxb.
French Polynesia Tuamotu Archipelago	Niau Atoll	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) As Senna tora (Linnaeus) Roxburgh. Voucher cited: J. Florence 10097 (PAP) Adventice
French Polynesia Tuamotu Archipelago	Niau Atoll		Bishop Museum (Honolulu) (1990) (voucher ID: BISH 633898) Taxon name on voucher: Senna tora (L.) Roxb.
French Polynesia Tuamotu Archipelago	Rangiroa (Rairoa) Atoll	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Adventice
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 98)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 700) Voucher cited: Akira s.n. (BISH)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Oppenheimer, Hank (2011) (p. 7) Voucher cited: Oppenheimer H10919 (BISH, PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Staples, George W./Imada, Clyde T./Herbst, Derral R. (2003) (p. 12) Voucher cited: M.C. Neal & C. Hartt s.n. (BISH 614694)
New Caledonia New Caledonia Archipelago	Île Grande Terre		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1982) (voucher ID: PTBG 28356) Taxon name on voucher: Senna obtusifolia
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 98)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 86)
Palau Palau (Belau ) (main island group)	Babeldaob Island		Beleu National Museum (Republic of Palau. Koror.) (1978) (voucher ID: BNM 10164) Taxon name on voucher: Senna obtusifolia L.
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 98)
Palau Palau (Belau ) (main island group)	Peleliu (Beliliou) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 91)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced	ILDIS Co-ordinating Centre (2013)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Waterhouse, D. F. (1993) (pp. 68, 78)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Northern Territory	introduced invasive	Smith, Nicholas M. (2002) (pp. 38-39)
Australia Australia (continental)	Northern Territory	introduced invasive	Australian Biological Resources Study (2013)
Australia Australia (continental)	Queensland	introduced invasive	Smith, Nicholas M. (2002) (pp. 38-39)
Australia Australia (continental)	Queensland	introduced invasive	Australian Biological Resources Study (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)	introduced	ILDIS Co-ordinating Centre (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	uncertain if native	ILDIS Co-ordinating Centre (2013)
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 68, 78)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 184)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 68, 78)
Mexico Mexico	Mexico (United Mexican States)	uncertain if native	ILDIS Co-ordinating Centre (2013)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 79) Naturalised
South America (Pacific rim) South America (Pacific rim)	Colombia	uncertain if native	ILDIS Co-ordinating Centre (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	uncertain if native	ILDIS Co-ordinating Centre (2013)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	uncertain if native	ILDIS Co-ordinating Centre (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 68, 78)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
La Réunion (France) La Réunion Island	La Réunion Island	introduced	ILDIS Co-ordinating Centre (2013)
French Territory of Mayotte Mayotte Islands	Mayotte Island	introduced invasive	Comité français de l'Union Internationale pour la Conservation de la Nature en France (2013)
Seychelles Seychelles Islands	Seychelles Islands	introduced	Weber, Ewald (2003) (p. 400)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	uncertain if native	ILDIS Co-ordinating Centre (2013)

Comments:  Invasive in woodlands in Australia.

A declared noxious weed in Western Australia and the Northern Territory (Smith, 2002; pp. 38-39).

Control: 

Physical:  "Single plants can be grubbed before flowering commences.  Larger colonies are slashed to reduce the plant's vigor"  (Weber, 2003; p. 400).

Chemical:  "Effective herbicides include 2,4-D plus picloram, glyphosate, or dichlorprop.  Seedlings are best sprayed before they set flowers"  (Weber, 2003; p. 400).  "Sensitive to dicamba and triclopyr but not to MCPA"  (Motooka et al., 2003).