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Weed Identification

prickly sida



Scientific Name

Sida spinosa

Other Common Names:

prickly mallow
spiny sida
Indian mallow
prickly fanpetals

Synonyms (former Scientific Names):

Sida augustifolia
Sida alba


A summer annual with yellow flowers and very small spines at the base of each leaf and branch. This weed is one of the ten most common and troublesome weeds in peanuts, cotton, and soybeans in most of the southern states.


Arranged alternately along the stem, approximately 3/4 to 2 inches (2 to 5 cm) long, and inconspicuously hairy. Leaves are oval to lanceolate in outline with toothed margins. Leaves occur on petioles that are 1/2 to 1 1/4 inches (1 to 3 cm) long and have small spines (stipules) that are 5 to 8 mm long at the base of each leaf petiole.

Identifying Characteristics

The seedlings with 2 heart-shaped cotyledons, and the small spines that occur at the base of each leaf petiole are both features that help in the identification of prickly sida. Velvetleaf (Abutilon theophrasti), Spurred Anoda (Anoda cristata), and Arrowleaf Sida (Sida rhombifolia) seedlings are very similar to those of prickly sida. However, prickly and arrowleaf sida have 2 heart-shaped cotyledons unlike the round and heart-shaped cotyledons of velvetleaf. Spurred anoda also has two heart-shaped cotyledons like prickly and arrowleaf sida, however the first true leaf of spurred anoda is not as coarsely toothed as that of prickly or arrowleaf sida. The cotyledons of arrowleaf sida are essentially identical to those of prickly sida, however the first true leaf of arrowleaf sida is rhombic in outline and tapers to the base unlike the first true leaf of prickly sida.

Flower Seed Head

Occur singly or in clusters on flower stalks (peduncles) that arise from the area between the stems and leaf petioles. Flowers consist of 5 orange yellow petals that are 1/8 to 1/4 inches (4 to 6 mm) long.

Seed Fruit

Fruit are capsules 1/8 to 1/4 inch (4 to 6 mm) long containing 5 individual segments each containing one seed. Each segment has 2 spikes or beak like protrusions on the tip that are pubescent. The seed are small egg shape, smooth, and dark brown,

Where Found

Prickly sida is primarily a weed of agronomic crops, but can also be found in horticultural crops, landscapes, pastures, hay fields, and gardens.

Growth Habit

upright and nonwoody

Thorns or Spines


Approximate Flower Diameter


Dominant Flower Color


Flower Symmetry

radial symmetery

Leaf Hairs

has hairs
no hairs

Leaf Shape


Leaf Arrangement


Leaf Margin


Leaf Structure


Leaf Stalk

shorter than leaf

Stem Hairs

has hairs

Stem Cross Section

round or oval

Milky Sap

not present

Root Structure


Life Cycle

summer annual


not present

Plant Type