Senna pendula (Willd.) H. S. Irwin & Barneby, Fabaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Spanish: valamuerto

Habit:  shrub

Description:  "Scandent or weakly erect, foetid shrubs 2-6 m tall. Leaflets (2) 3-6 (7) pairs, the distal ones larger, broadly to narrowly obovate or obovate-cuneate, (1.8-) 2.2-5.5 (-6.5) cm long, (0.7-) 1-2 (-2.4) cm wide, upper surface green, glabrous, lower surface slightly glaucous, glabrous or sparsely pubescent toward base or along midrib, apex rounded, mucronulate or shallowly emarginate, base obliquely cuneate, petiolar nectaries always between the first and sometimes also second pairs of leaflets, 0.7-2.8 mm long, stipules linear-lanceolate to linear-oblanceolate, 1.5-9 mm long, caducous.  Flowers in racemes 3-30 cm long, pedicels 8-37 mm long, bracts subulate-lanceolate, 1-4 mm long, caducous as pedicels begin to elongate; calyx lobes yellowish to reddish brown, outer ones ovate to elliptic-lanceolate, 3-10 mm long, the innermost obovate to elliptic-suborbicular, 7-15.5 mm long, margins membranous; petals golden yellow to orangish yellow, fading yellow, the standard broadly obovate-flabellate, the others ovate to obovate, the abaxial ones sometimes oblong-elliptic, the longest one 11-26 mm long; staminodes linear-oblanceolate to rhombic-orbicular or inversely deltate, 1.2-4.5 mm long; filaments of 4 median stamens 1.4-4 mm long, those of lateral abaxial stamens dilated, 6.5-20 mm long, that of central abaxial stamen 1.6-7 mm long; anther of central abaxial stamen sterile, fertile anthers dehiscent by U-shaped slits.  Pods pendulous, chartaceous, cylindrical or compressed-cylindrical, straight or slightly curved, often portions sterile and then variable distorted, 7-18 cm long, tardily or not dehiscent, the mesocarp and exocarp separating when fruit fully ripe, the cavity with membranous interseminal septa.  Seeds in 1-2 rows, brown, smooth and glossy or dull, obliquely obovoid, perpendicular to capsule axis, embedded in copious or scanty pulp, 4.1-6.6 mm long, without an areole"  (Wagner et al., 1999; p. 701).

Var. advena:  "Differs from other varieties by the long anthers abruptly constricted into a beak as long as or longer than the diameter of the pore, styles 5-8 mm long, obdeltate staminodes, the longest sepal 9.5-13 mm long, longest petal 12-16 mm long, and cylindrical plods 8-15 cm long, with 2 rows of seeds"  (Wagner et al., 1999; p. 701).

Habitat/ecology:  "Woodland, riparian habitats, tropical hammocks, coastal beaches.  This is a variable species, belonging to a complex with numerous varieties.  It is a fast growing plant often becoming established in openings of hammocks and climbing over the adjacent canopies, suppressing the growth of native species and displacing them.  It is quite salt tolerant and grows well in sandy soils.  The plant resprouts from the base after damage"  (Weber, 2003; p. 401).

In Hawai‘i, "cultivated and naturalized at low elevations often in dry, disturbed areas, 15-670 m"  (Wagner et al., 1999; p. 701); "forms dense stands in pastures and other disturbed areas; seems to be more of a problem in drier areas"  (Motooka et al., 2003).  In Queensland, Australia, "naturalized in highly disturbed urban bushland and farmland, primarily along roadsides and the banks of watercourses"  (Csurhes & Edwards, 1998; p. 130).

Propagation:  Seed.  "Seed production is prolific and the long-lived seeds are dispersed by water and soil movement"  (Weber, 2003; p. 401).

Native range:  New World tropics and subtropics (Wagner et al., 1999; p. 701).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 701) Var. advena
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 701) Var. advena
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 701) Var. advena
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 701) Var. advena
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 701) Var. advena
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 701) Var. advena

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)	New South Wales	introduced invasive cultivated	Csurhes, S./Edwards, R. (1998) (p. 130)
Australia Australia (continental)	New South Wales	introduced invasive cultivated	Australian Biological Resources Study (2008) Var. glabrata (Vogel) H.S. Irwin & Barneby
Australia Australia (continental)	Queensland	introduced invasive cultivated	Csurhes, S./Edwards, R. (1998) (p. 130)
Australia Australia (continental)	Queensland	introduced invasive cultivated	Australian Biological Resources Study (2008) Var. glabrata (Vogel) H.S. Irwin & Barneby
Mexico Mexico	Mexico (United Mexican States)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2009)

Control: 

Physical:   "Seedlings and smaller plants can be removed manually" (Weber, 2003; p. 401).

Chemical:  "Larger plants are cut and the cut stumps treated with herbicide.  Foliar sprays are most effective on seedlings and on fresh regrowth"  (Weber, 2003; p. 401).  "Based on work with other sennas, probably sensitive to dicamba and triclopyr and tolerant of MCPA"  (Motooka et al., 2003).

Additional information:
Information from the book "Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide" (Motooka et al., 2003). (PDF format).
Information from the book "Identification and biology of non-native plants in Florida's natural areas" (PDF format).

Additional online information about Senna pendula is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Senna pendula as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Senna pendula may be available from the Germplasm Resources Information Network (GRIN).

References:

Australian Biological Resources Study. 2008. Flora of Australia Online. Australian Biological Resources Study, Canberra.

Csurhes, S./Edwards, R. 1998. Potential environmental weeds in Australia: Candidate species for preventative control. Canberra, Australia. Biodiversity Group, Environment Australia. 208 pp.

Langeland, K. A./Burks, K. Craddock. eds. 1998. Identification and biology of non-native plants in Florida's natural areas. Gainesville, FL: University of Florida. 165 pp.

Motooka, Philip/Castro, Luisa/Nelson, Duane/Nagai, Guy/Ching, Lincoln. 2003. Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa. 184 pp.

U. S. Government. 2009. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2009. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.