FAMILY: Compositsae (Asteraceae)—the Daisy Family (see Arctium)
PHENOLOGY: Cocklebur flowers July through October.
DISTRIBUTION: It is found in fields, waste places, flood plains, and on lake and sea beaches.
PLANT CHARACTERISTICS: These include heads: small, unisexual; staminate heads: uppermost, many-flowered; involucre: of separate bracts in 1-3 series; receptacle: cylindric, chaffy; filaments: monadelphous; pistillate heads: completely enclosing the two flowers, forming a conspicuous 2-chambered bur with hooked prickles; pistillate flowers: corolla absent; styles exsert from the involucre; achenes: thick, solitary in chambers of the bur; pappus: absent; plants: annuals, coarse, weedy; leaves: coarse, alternate.
POISONOUS PARTS: Cocklebur poisoning is always associated with ingestion of seedlings. Seeds and seedlings are toxic and remain toxic when dry. Seeds are toxic at a rate of 0.3% of the animal's body weight; seedlings, at a rate of 1.5%.
SYMPTOMS: Anorexia, depression, nausea, vomition, weakened heartbeat, muscular weakness, dyspnea, and prostration are symptoms of poisoning. Spasmodic running motions or convulsions are observed when animals are prostrate. Also, abdominal pain is present in pigs. Fowl, which may be poisoned by the seeds, show profound depression. Symptoms may appear within 2 days; death occurs within a few hours to 3 days after a toxic dose. Postmortem: gross lesions: gastroenteric irritation and congestion; serofibrinous ascites, gallbladder wall edema; accentuation of liver lobes; histological lesions: acute' diffuse, centrilobular and paracentral coagulative necrosis of the liver.
POISONOUS PRINCIPLES: The agent of toxicosis, hydroquinone, is used commercially in photographic processes. Ingestion of 1g has caused tinnitus, nausea, vomiting, sense of suffocation, shortness of breath, cyanosis, convulsions, delirium, and collapse. Death has followed ingestion of 5 g.
CONFUSED TAXA: Burdock (Arctium) may be confused with cocklebur (Xanthium), however, the involucral bracts in the former are distinctly hooked at the tip, a feature not found in the latter (see Arctium).
SPECIES OF ANIMALS AFFECTED: All species of livestock are susceptible.
TREATMENT: (11a)(b); (26)