Senna septemtrionalis
(smooth senna)

Pictures

Picture	Title	Caption	Copyright
Title Flowers and foliage Caption Senna septemtrionalis (smooth senna, kolomona, kalamona); flowers and foliage. Makawao Forest Reserve, Maui. November, 2004 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Flowers and foliage	Senna septemtrionalis (smooth senna, kolomona, kalamona); flowers and foliage. Makawao Forest Reserve, Maui. November, 2004	©Forest Starr & Kim Starr - CC BY 4.0

Identity

Preferred Scientific Name

• Senna septemtrionalis (Viv.) H.S. Irwin & Barneby

Preferred Common Name

• smooth senna

Other Scientific Names

• Adipera laevigata (Willd.) Britton & Wilson
• Cassia aurata Roxb.
• Cassia elegans Kunth
• Cassia floribunda sensu De Wit non Collad.
• Cassia laevigata Willd.
• Cassia quadrangularis Zoll. & Moritzi
• Cassia septemtrionalis Viv.
• Cassia vernicosa Clos
• Chamaecassia laevigata (Willd.) Link
• Chamaefistula laevigata (Willd.) G. Don
• Chamaesenna laevigata (Willd.) Pittier
• Senna aurata Roxb.

International Common Names

• English: arsenic bush; Brazilian buttercup; buttercup bush; dooleyweed; laburnum; senna; smooth leaved senna; yellow shower
• Spanish: leno hediondo (Spain); retama (Honduras)
• French: séné septentrional
• Chinese: guang ye jue ming

Local Common Names

• Brazil: canudo-de-pito
• Dominican Republic: brusca
• Fiji: winivinikau
• Guatemala: moco
• Indonesia/Java: senting; tayoomas; trembalon
• Indonesia/Nusa Tenggara: kasingsat; keetjandoong
• Madagascar: moco; retama; tsotsorinangatra; voandranomainty
• Mexico: cafecillo
• Nicaragua: café; coralillo; frijolillo; pico de pájaro
• Puerto Rico: hedionda macho
• South East Asia: bo cap nuroc

EPPO code

• CASLA (Cassia laevigata)

Summary of Invasiveness

S. septemtrionalis is a leafy shrub or small tree which abundantly produces seeds that are easily dispersed by humans (machinery and vehicles), birds and animals, and by water (West, 2003). Once established in new areas, this species matures quickly, negatively impacting native flora. The species is listed in the Global Compendium of Weeds as an “agricultural weed, cultivation escape, environmental weed, garden thug, naturalized, weed” with records of occurrences in North and Central America, South America, Asia, Asia-Pacific, Africa, Australia, and Europe (Randall, 2012; DAISIE, 2014; USDA-ARS, 2014). It is considered invasive in Fiji, Australia, Ecuador, Hawaii, New Zealand, and a weed in South Africa and the United States (see Distribution Table; Randall, 2012; PIER, 2014). It is also recorded as invasive in Burundi, Ethiopia, Kenya, Malawi, Rwanda, Tanzania and Uganda. The species was given an Australian rating of 4, indicating it is “naturalised and known to be a major problem at 3 or fewer locations within a State or Territory” (Groves et al., 2003); according to the Global Compendium of Weeds, the species is indeed invasive in some parts of the country (Randall, 2012).

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Fabales
•                         Family: Fabaceae
•                             Subfamily: Caesalpinioideae
•                                 Genus: Senna
•                                     Species: Senna septemtrionalis

Notes on Taxonomy and Nomenclature

Until the beginning of the 1980s the genus Cassia was considered to be a very large genus of over 500 species. Bentham (1871) wrote that three groups within the Cassia genus were so distinct from one another that any species can always be unequivocally allocated to one of them; some main distinctions included fruit structure, stamen structure and arrangement, and nodulation (Lock, 1988). However it was not until 1982 that Irwin and Barneby formally separated Cassia into three genera: Cassia L. emend. Gaertner, Senna Miller, and Chamaecrista Moench; Cassia now has only about 30 species, whereas Senna and Chamaecrista comprise about equal numbers of species, about 260 and 270 respectively (Irwin and Barneby, 1982; Sosef and Maesen, 1997). These three genera are now largely accepted and together make up subtribe Cassinae. Cassia and Senna differ principally in stamen organization, and in arid areas of Australia, taxonomic distinctions between and within the three genera are blurred by polyploidy, hybridization and apoximis (Lewis et al., 2005). In 1988 Lock presented new names and combinations for the Cassinae species in Africa, noting that “if Cassia were to continue to be used in its broad sense in Africa, there would be several species which would be consistently given different names in different continents” (Lock, 1988). 

Approximately 80% of the Senna genus’ 260 or so species occur in New World tropical and subtropical areas, extending into warm temperate and rarely into cool temperate areas of both hemispheres with species in Africa, Madagascar, Australia, and a few in southeastern Asia and Pacific islands (Irwin and Barneby, 1982; Lock, 1988; Wagner et al., 2014). 

There has been much taxonomic confusion over this species. The name Cassialaevigata was widely used for a long period, but when De Wit misapplied the name Cassia floribunda, that name came into general usage. Irwin and Barneby (1982) have now shown that the oldest name is Cassiaseptemtrionalis, and that the epithet floribunda should correctly be applied, as Senna × floribunda (Cav.) H.S. Irwin & Barneby, to the hybrid between S. septemtrionalis and S. multiglandulosa. (Brummitt et al., 2007) Historical data found under synonym names have been indicated in this datasheet.

Description

Leafy shrubs or small trees 1-5 (-6.5) m tall. Leaflets 3-4 (5) pairs, the distal ones larger, broadly ovate to lanceolate, (3.5-) 4.5-10.5 cm long, (1.1-) 1.4-3.5 cm wide, glabrous, lower surface pale, apex acuminate or caudate, base obliquely rounded or cuneate, petiolar nectaries between all pairs or all but the distal pair of leaflets, none contiguous to pulvinus, the lowest one 1-2 mm long, stipules submembranous, narrowly lanceolate, 3-7 mm long, caducous. Flowers in racemes (1.5-) 2.5-8 cm long, pedicels (12-) 15-25 mm long, bracts sub-membranous, linear, lanceolate, or subulate, (1.5-) 2-4.5 mm long, caducous as pedicels begin to elongate; calyx lobes yellowish green, yellowish brown, or completely yellow, the outer ones relatively firm, ovate-elliptic, 4-6.5 mm long, the inner ones submembranous, oblong-obovate or suborbicular, 6.5-10 mm long; petals bright yellow, the standard obovate to obovate-flabellate, deeply emarginate, the others obovate, the longest petal 12-16 mm long; staminodes 3, obovate or suborbicular, (1.7-) 2-2.6 mm long; filaments of 4 median stamens 1.3-2.2 mm long, those of 2 abaxial stamens dilated, ribbon-like, 7-10.5 mm long, that of abaxial central stamen 2-4 mm long. Pods ascending on a stiff pedicel, chartaceous, cylindrical or obtusely quadrangular, 6-10.5 cm long, 0.8-1.1 cm wide, cavity moderately pulpy, divided into 2 parallel rows of of cells. Seeds oriented with broad face to the septum, olive or brown, compressed-obovoid, 3.6-4.9 mm long, constricted at the hilum, smooth or minutely pitted, without an areole (Wagner et al., 2014).

Plant Type

Distribution

S. septemtrionalis is native to Mexico and Central America, specifically at 1000-1950 m altitudes along or near the crest and Gulf Slope of Sierra Madre Oriental from southeast San Luis Potosi to north Oaxaca and Veracruz, and from the highlands of west and south Oaxaca and Chiapas southeast through montane Guatemala, Honduras and Nicaragua just into Costa Rica, and in Mexico extending west at scattered points along the Transverse Volcanic Range into Michoacan. It has been introduced and naturalized in the West Indies, parts of South America, tropical Africa, India, Southeast Asia and the Pacific (see History of Introduction section) (Irwin and Barneby, 1982). It has been speculated that the species was introduced to Nicaragua a long time ago (Missouri Botanical Garden, 2014). 

In Irwin and Barneby’s (1982) revision of the former Cassia genus, S. septemtrionalis is defined as native only in the northern hemisphere and probably only in highland Mexico and Central America, while the habitally similar sennas of Brazil have been named distinct species, S. tropica and S. araucarietorum.

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

S. septemtrionalis has been cultivated for several centuries as an ornamental and certainly since pre-Columbian times for traditional medicinal uses in Mexico (Irwin and Barneby, 1982). The species has been widely introduced outside its native range of Central America to other tropical and temperate regions, where it is now naturalized in many places (Randall, 2012). It has been recorded as escaped from cultivation in India (Kumar and Sane, 2003). In Africa it was first collected in eastern Zimbabwe in 1906, where it was being used medicinally by local people (Brummitt et al., 2007). 

In the West Indies, Irwin and Barneby (1982) report that the species has been naturalized in Jamaica since the eighteenth century. It was certainly present in Jamaica before 1689, when Sir Hans Sloane collected a specimen as part of his voyage between 1687-1689 that resulted in the publications CatalogusPlantarum, 1696, and Natural History of Jamaica, 1707 (UK Sloane Herbarium Specimen 737). The species’ native status in Cuba and Puerto Rico is uncertain, but it was observed in Puerto Rico as early as 1881 and was included (as Cassia laevigata Willd.) in Bello’s Flora of Puerto Rico (Bello Espinosa, 1881; Acevedo-Rodriguez and Strong, 2012). The presence of this species was also reported (as C. laevigata Willd.) between 1903-1911 in Jamaica, Martinique, tropical America, western tropical Africa, and Australasia (Urban, 1905). Other places with reports of the species (date of introduction unknown, but after the eighteenth century) include the Dominican Republic (naturalized); Martinique, Barbados and the Gulf of Panama (weedy or cultivated only); upland Colombia, Pacific Peru, Distrito Federal in Brazil, and gardens in Argentina and Chile (collected infrequently and unknown status but unlikely to be wild); tropical Africa, India, Sri Lanka, Malay Penninsula, Java and Sumatra, eastern Australia and Pacific islands including Fiji and Hawaii (long established); and Florida and tropical North America (widespread in horticulture and under glass) (Irwin and Barneby, 1982).

Risk of Introduction

The risk of introduction for this species is high. It has been intentionally introduced and cultivated in many tropical and subtropical regions across the world as green manure, fodder, and a hedge plant, for medicinal and food uses, and for ornamental purposes (Sosef and Maesen, 1997; Hanelt et al., 2001; ILDIS, 2014; USDA-ARS, 2014). The species is known to escape from cultivation and has been shown to mature rapidly, spreading and persisting in a variety of environments (West, 2003; Kumar and Sane, 2003). Due to the ease of seed dispersal by both biotic and abiotic vectors, the high production and long viability of its seed bank, and its rapid growth rate, probability of invasion remains high, especially around cultivated areas (West, 2003).

Habitat

S. septemtrionalis is originally a shrub or treelet of sunny microhabitats in cool or moist oak, oak-pine and mixed pine-liquidambar forest, with secondary habitats as a prolific shrubby weed of disturbed or ruderal places (Irwin and Barneby, 1982). Plants of the species can establish themselves primarily at low elevations but up to 2500 m in a variety of habitats, including dry, disturbed areas, along roadsides, in dry and wet forest margins, along stream banks, in alluvial sand or silt, in neglected gardens, abandoned orchards or in fallow lands, and occasionally in open woodlands or as undergrowth plants, particularly of eucalyptus or wattles (Sosef and Maesen, 1997; PIER, 2014; JSTOR Global Plants, 2014; Weeds of Australia, 2014). In Madagascar, the species is found in open and disturbed vegetation including savoka, in cultivated areas, and is frequently seen along roadsides in the more humid areas of upland eastern Madagascar (Puy et al., 2002).

Habitat List

Biology and Ecology

Genetics

Gametophytic chromosome count has been recorded as 2n = 14 (IPCN Chromosome Reports (2014); 2n= 28, 56 (Wagner et al., 2014).

Reproductive Biology

S. septemtrionalis has an abundant and persistent seed bank with a longevity estimated to be decades; a 1908 experiment demonstrated the seeds could still germinate (25% success) after remaining at room temperature for 16 years (Ewart, 1908). In Madagascar the species flowers between December-May (Puy et al., 2002). 

Longevity

Plants of this species are short-lived perennials (Brummitt et al., 2007). 

Environmental Requirements

S. septemtrionalis can establish itself in alluvial sand or silt. It can grow in both non-acidic and acidic soils, preferring more humid tropical zones. It grows at altitudes usually ranging from 0-1500 m, although in Nepal it can occur at 2200 m (Owino, 1992; Puy et al., 2002; Flora of Nepal Editorial Committee, 2013; JSTOR Global Plants, 2014).

Climate

Soil Tolerances

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• light
• medium

Means of Movement and Dispersal

In addition to repeated intentional introduction and cultivation of the species across tropical and subtropical regions of the world for ornamental, agroforestry, and food purposes, S. septemtrionalis has also been shown to have escaped cultivation and been accidentally introduced to the wild (Sosef and Maesen, 1997; Kumar and Sane, 2003; Brummitt et al., 2007; Weeds of Australia, 2014). The species reproduces mainly by seeds, which are numerous and easily dispersed by water or by mud carried by humans, animals and machinery, or as a contaminant in agricultural produce (Weeds of Australia, 2014). It can be further spread by birds or through mass movement of soil and flood debris (West, 2001).

Pathway Causes

Pathway Vectors

Impact Summary

Environmental Impact

Despite being widely cultivated as an ornamental as well as a shade and hedge plant and green manure for agroforestry purposes, S. septemtrionalis has been shown to have a negative impact on its local environment due to its rapid maturity rate, abundant seed production, long-lived seed bank, and multiple biotic and abiotic vectors for seed dispersal (West, 2003). The species was identified as the most widespread and difficult to remove invasive species on Raoul Island, New Zealand, and is considered an environmental and agricultural weed in the Global Compendium of Weeds (West, 2003; Randall, 2012). The seeds and other plant parts are also suspected to be mildly toxic to humans and grazing animals, but there is insufficient evidence to substantiate the claims; it is also possible that the negative health effects can be negated by cooking the pulses before eating (Sosef and Maesen, 1997; CANBR, 2014).

Risk and Impact Factors

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Highly mobile locally
• Benefits from human association (i.e. it is a human commensal)
• Long lived
• Fast growing
• Has high reproductive potential
• Has propagules that can remain viable for more than one year
• Reproduces asexually

• Damaged ecosystem services
• Ecosystem change/ habitat alteration
• Negatively impacts agriculture
• Reduced native biodiversity
• Threat to/ loss of endangered species
• Threat to/ loss of native species

• Competition - monopolizing resources
• Rapid growth

• Highly likely to be transported internationally accidentally
• Highly likely to be transported internationally deliberately

Uses

S. septemtrionalis has been cultivated as an ornamental plant for over 200 years and, since pre-Columbian times, used for folk medicine, so the primary range of dispersal has been thereby modified and lost to view (Irwin and Barneby, 1982). It is grown in plantations as a shade tree and as green manure, and in Java, Ethiopia and other places it is valued as a hedge plant. In Madagascar the seeds are crushed and added to coffee as a Malagasy beverage, and in Guatemala they are used as a coffee substitute. The unripe seeds, young shoots, and the leaves are eaten cooked in Sumatra and parts of India (Sosef and Maesen, 1997; Puy et al., 2002; Hanelt et al., 2001).

Uses List

Animal feed, fodder, forage

• Fodder/animal feed

Environmental

• Agroforestry
• Boundary, barrier or support
• Soil improvement

Human food and beverage

• Beverage base
• Pulse
• Vegetable

Materials

• Green manure

Similarities to Other Species/Conditions

As Puy et al. (2002) note, there has been discussion regarding a similar species to S. septemtrionalis which is represented in the herbarium at Kew by four sheets collected during the 1880s (Baron 331, 4139, 5042; Hildebrandt 4100). This species has leaves with narrower, elliptic leaflets, which are obtuse apically and thinly pubescent. Irwin and Barneby (1982) identify this species as S. x floribunda (Cav.) H.S.Irwin and Barneby. In 1935, J. Ghesquiere identified the Baron 4139 specimen as Cassia tomentosa L.f. (=Senna multiglandulosa (Jacq.) H.S. Irwin & Barneby) (Ghesquiere, 1935), but Puy et al. (2002) states that this is incorrect, and that the species, while obviously related to S. septemtrionalis, is “undoubtedly an introduced plant and its true identity remains questionable”.

Prevention and Control

In Raoul Island, New Zealand, S. septemtrionalis is the top priority of an alien plant species eradication effort which began in 1972. As of 2001, the program had been able to reduce the species presence from over 300,000 to 50,000. Methods of control used by this program included physically hand removing seedlings, adolescent plants, and burning the fruits of mature individuals before cutting them down and painting stumps with herbicides. Specifically for S. septemtrionalis, removal of undergrowth and disturbance of the soil was determined to hasten depletion of the seed bank (West, 2003).

References

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Links to Websites

Contributors

27/3/2014 Original text by:

Marianne Jennifer Datiles, Department of Botany-Smithsonian NMNH, Washington DC, USA

Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA

Distribution Maps