Spanish needles
Family
FabaceaeScientific Name
Bidens bipinnata
Synonyms (former Scientific Names):
Bidens bipinnata var. biternatoides
Habit
Summer annual with dissected leaves and yellow flowers reaching 5 1/2 feet in height.
Leaves
The leaves are dissected with 2 to 3 rows of lateral leaflets that are ovate or lanceolate in shape. The leaves have short hairs along the edges and veins that are pressed closely to the leaves.
Identifying Characteristics
Stems: Erect, square in cross-section, branching in the upper section, and with small tufts of hairs at the nodes. Summer annual with leaves that are dissected 2 to 3 times and have yellow flowers. Spanish needles seedlings are similar in appearance to those of Common Ragweed (Ambrosia artemisiifolia), however the cotyledons of common ragweed are much more rounded than those of spanish needles. Additionally, common ragweed seedlings do not have the characteristic maroon highlights on the cotyledon and leaf undersurfaces like those of spanish needles. Devils Beggarticks (Bidens frondosa) is also similar in appearance to spanish needles; devils beggarticks does not have leaves that are dissected 2 to 3 times, however. Spanish needles can also be confused with Coreopsis Beggarticks (Bidens polylepis). Coreopsis beggarticks, however, has flowers that are much larger and showier and leaflets that are more linear than those of spanishneedles.
Flower Seed Head
The yellow flowers are composed of small disk flowers toward the center, and larger ray flowers along the edge. Occasionally, the ray flowers will be absent, but are usually 10 to 15 mm long and 3 mm wide. The flowering heads are often surrounded by green bracts.
Seed Fruit
The seeds develop in an achene that is approximately 8 to 18 mm long, linear in outline, and dark brown in color. The achenes have 3 to 4 spines at the apex that are pointed downward.
Where Found
Spanish needles prefer dry waste places such as roadsides, pastures, and other noncrop areas. It can be found along the eastern United States.
Growth Habit
Varies:
upright and nonwoody,
prostrate and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
pencil
Dominant Flower Color
Varies:
yellow,
orange
Flower Symmetry
Varies:
bilateral symmetry,
not symmetrical
Leaf Hairs
Varies:
has hairs,
no hairs
Leaf Shape
Varies:
lance,
oval
Leaf Arrangement
opposite
Leaf Margin
Varies:
lobed,
serrated
Leaf Structure
simple
Leaf Stalk
Varies:
shorter than leaf,
longer than leaf
Stem Hairs
Varies:
has hairs,
no hairs
Stem Cross Section
round or oval
Milky Sap
not present
Root Structure
fibrous
Life Cycle
biennial
Ochrea
not present
Plant Type
Herb