Senna obtusifolia (L.) Irwin & Barneby

sickle-pod wild senna

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Sickle-pod wild senna is native to southeastern North America and invasive in California and many other parts of the world. It can be a serious weed of crops, but is itself edible and has traditional medicinal uses. In New England it is considered non-native and has been collected only in Massachusetts.

Habitat

Anthropogenic (man-made or disturbed habitats)

Characteristics

Habitat
terrestrial
Flower petal color
  • orange
  • yellow
Leaf type
the leaves are compound (made up of two or more discrete leaflets
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
the edge of the leaf blade is entire (has no teeth or lobes)
Flower symmetry
there is no way to evenly divide the flower (the flower is asymmetrical)
Number of sepals, petals or tepals
there are five petals, sepals, or tepals in the flower
Fusion of sepals and petals
  • both the petals and sepals are separate and not fused
  • the petals or the sepals are fused into a cup or tube
Stamen number
7
Fruit type (general)
the fruit is dry and splits open when ripe
Fruit length
100–200 mm
Show All Characteristics
  • Clonal plantlets
    Bulbils
    the plant does not appear to have bulbils
    Bulblets replace flowers
    there are no bulblets where the flowers are located
  • Flowers
    Anther attachment
    the anther is attached by its base to the filament
    Anther opening
    the anthers have small holes or openings at the tips
    Anther spurs
    the anthers do not have spurs on them
    Calyx symmetry
    there is only one way to evenly divide the calyx (the calyx is bilaterally symmetrical)
    Carpels fused
    • NA
    • the carpel is solitary or (if 2 or more) the carpels are not fused to one another
    Cleistogamous flowers
    there are no cleistogamous flowers on the plan
    Corolla morphology
    NA
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Filament surface
    the filament is smooth, with no hairs or scales
    Flower description
    the flower has a superior ovary and a hypanthium
    Flower diameter
    15–26 mm
    Flower petal color
    • orange
    • yellow
    Flower reproductive parts
    the flower has both pollen- and seed-producing parts
    Flower symmetry
    there is no way to evenly divide the flower (the flower is asymmetrical)
    Flowers sunken into stem
    no
    Form of style
    the style is narrow at the tip and unbranched
    Fused stamen clusters
    NA
    Fusion of sepals and petals
    • both the petals and sepals are separate and not fused
    • the petals or the sepals are fused into a cup or tube
    Horns in hoods (Asclepias)
    NA
    Hypanthium
    the flower has a hypanthium
    Inflorescence one-sided
    the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks
    Inner tepals (Rumex)
    NA
    Length of flower stalk
    10–20 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    1
    Number of pistils
    1
    Number of sepals, petals or tepals
    there are five petals, sepals, or tepals in the flower
    Number of styles
    1
    Ovary position
    the ovary is above the point of petal and/or sepal attachment
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal and sepal colors
    • orange
    • yellow
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal folding in bud
    the petals in bud are arranged in a cycle with edges overlapping like roof shingles (imbricate)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal length
    10–15 mm
    Petal number
    5
    Petal tips (Cuscuta)
    NA
    Raceme attachment (Veronica)
    NA
    Scales inside corolla
    no
    Sepal and petal color
    the sepals are different from the petals
    Sepal appearance
    the sepals are green or brown, and leaf-like in texture
    Sepal appendages
    the sepals do not have appendages on them
    Sepal appendages (Oenothera)
    NA
    Sepal color
    green to brown
    Sepal length
    3–8 mm
    Sepal number
    5
    Sepal shape
    the sepal outline is eliiptic (widest near the middle and tapering at both ends)
    Sepals fused only to sepals
    the sepals are separate from one another
    Stamen morphology
    the stamens within a cycle differ in length or width
    Stamen number
    7
    Stigma position
    the stigmas are positioned at the tip of the style
    Style petal-like
    the styles are not petal-like
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    NA
  • Fruits or seeds
    Achene relative orientation
    NA
    Achene shape
    NA
    Achene surface (Polygonum)
    NA
    Achene type
    NA
    Berry color
    NA
    Capsule color (Viola)
    NA
    Capsule ribs
    NA
    Capsule splitting
    • NA
    • the capsule splits by two main valves, teeth or pores
    Fruit (pyxis) dehiscence
    NA
    Fruit cross-section
    the fruit is roughly quadrangular in cross-secgtion
    Fruit features (Brassicaceae)
    NA
    Fruit length
    100–200 mm
    Fruit length relative to sepals
    the fruit is longer than its associated sepals
    Fruit locules
    one
    Fruit shape
    the fruit is another shape than those described
    Fruit type (general)
    the fruit is dry and splits open when ripe
    Fruit type (specific)
    the fruit is a legume (a fruit that splits into two valves, but only has a single carpel; think of a pea pod)
    Fruit width
    3–4 mm
    Legumes (Fabaceae)
    the legume has internal partitions arranged cross-wise along the fruit
    Mericarp length
    0 mm
    Mericarp segment shape (Desmodium)
    NA
    Other markings on berry
    NA
    Ovary stipe
    the ovary or fruit has a stipe
    Placenta arrangement
    the plant has parietal placentation, where ovules develop on the wall or slight outgrowths of the wall forming broken partitions within a compound ovary
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Seed length
    4–5 mm
    Septum in fruit (Brassicaceae)
    NA
    Wings on fruit
    the fruit does not have wings on it
    prickles on fruits
    the fruits do not have thorn-like defensive structures
  • Glands or sap
    Glands on leaf blade
    the leaf blades do not have glandular dots or scales
    Sap
    the sap is clear and watery
    Sap color
    the sap is clear
  • Growth form
    Growth form
    the plant is an herb (it has self-supporting stems)
    Lifespan
    the plant lives only a single year or less
    Parasitism
    the plant is not parasitic
    Plant color
    the leaves or young stems of the plant are green
    Plants darken when dry
    no
    Spines on plant
    the plant has no spines
  • Leaves
    Bracteole number (Apiaceae)
    0
    Bracteoles
    there are no bracteoles on the plant
    Bracts in plantain (Plantago)
    NA
    Final leaf segment length (compound lvs only)
    10–80 mm
    Final leaf segment length to width ratio (compound lvs only)
    1.3–1.8
    Floral bracts
    the flower does not have bracts
    Hairs on underside of leaf
    • the underside of the leaf is fuzzy or hairy
    • the underside of the leaf is not hairy, or it has very few hairs
    Hairs on upper side of leaf
    • the upper side of the leaf is fuzzy or hairy
    • the upper side of the leaf is not hairy, or it has very few hairs
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade base
    the leaf has a distinct leaf stalk (petiole)
    Leaf blade base shape
    the base of the leaf blade is rounded
    Leaf blade edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade primary vein pattern
    the secondary veins branch off at intervals from the primary vein
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip (it may or may not have secondary veins)
    Leaf duration
    the leaves drop off in winter (or they whither but persist on the plant)
    Leaf form
    the leaves are green, with an expanded blade and a leaf-like texture
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have leaf stalks
    Leaf teeth and lobes
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf tip
    the tip of the leaf blade is rounded, with no point
    Leaf type
    the leaves are compound (made up of two or more discrete leaflets
    Leaflet number
    2–3
    Leaves per node
    there is one leaf per node along the stem
    Pinnately compound leaf type
    the pinnately compound leaves lack a terminal leaflet (and usually have an even number of leaflets per axis)
    Specific leaf type
    the leaf has a row of two or more lobes on each side of the central axis
    Stipels
    there are no stipels at the bases of the petiolules
    Stipule features
    NA
    Stipule shape
    the stipules are another shape than the choices given
    Stipules
    the plant has stipules
    Teeth per side of leaf blade
    0
  • Place
    Habitat
    terrestrial
    Specific habitat
    man-made or disturbed habitats
  • Scent
    Plant odor
    the plant has an unpleasant smell
  • Stem, shoot, branch
    Branched tendrils
    NA
    Hair between stem nodes
    • the stem has hairs between the nodes
    • the stem has no hairs between the nodes
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Plant height
    5–100 cm
    Stem orientation
    the stems are upright or angled outwards
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils

Wetland Status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

New England Distribution and Conservation Status

Distribution

Connecticut
absent
Maine
absent
Massachusetts
present
New Hampshire
absent
Rhode Island
absent
Vermont
absent

Conservation Status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
unranked (S-rank: SNR)

Native to North America?

Yes and no (some introduced)

Sometimes Confused With

Senna hebecarpa

Synonyms

  • Cassia obtusifolia L.

Family

Fabaceae

Genus

Senna

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Information from Dichotomous Key of Flora Novae Angliae

2.  Senna obtusifolia (L.) Irwin & Barneby E

sickle-pod wild senna. Cassia obtusifolia L. • MA. Railroads, yards.