Xanthium strumarium (Rough cocklebur)

Rough cocklebur, Noogoora burr, clotbur, common cocklebur, large cocklebur, woolgarie bur

These plants may have originated in Eurasia and become naturalized in North America, or they may be North American natives too.

Plants: Cockleburs are 1–4′ (30–121 cm) tall, with erect, multiply branched stems that are ridged, rough, and hairy. Stems are green, flecked with perple-brown to black spots.

Leaves: The first pair of true leaves is opposite, triangular to egg shaped with a rounded tip, and slightly toothed, with three prominent surface veins. All other young leaves are alternate, distinctly toothed, egg shaped with a pointed tip, and covered in rough, short hairs that make the leaves feel gritty. Leaves have long petioles.

Flowers: Small green disc flowers, with male and female flowers on the same plant. Male flowers are ⅛–¼″ (5–7.6 mm) around. Femaile flowers are even smaller, contained within immature burs.

Fruits: The brown hard woody ovoid burs that form from female flowerheads are the most distinctive identifying feature. They are about 1 ⨉ ⅝″ (2.5 ⨉ 1.8 cm) in size, and covered with hooked prickles. Each bur contains two light brown to black seeds.

Habitats: Pastures, fields, roadsides, along stream banks, dunes or poorly drained areas.

Kingdom	Plantae	Plants, but not fungi, lichens, or algae (from Stearn's Botanical Latin)
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Asteridae	A large class that encompasses asters
Order	Asterales	Flowering plants with a central disk flower and surrounding petals, like daisies
Family	Asteraceae	The aster family, which also includes daisies and sunflowers; from the Greek ἀστήρ, “star,” for the star-shaped flowers
Genus	Xanthium	Cocklebur family, from Greek xanthos, “yellow”, possibly because a yellow dye can be prepared from this
Species	strumarium	Of or pertaining to tumors or ulcers

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