Ricinus communis —Castor bean; Palma Christi
FAMILY: Euphorbiaceae—the Spurge Family (see Codiaeum)
PHENOLOGY: Flowering is dependent on the time of year that the seeds are sown. Seeds may be sown in the place where the plants are to be grown or in pots and transplanted in mid-May. Flowering occurs in mid-summer.
DISTRIBUTION: This plant, introduced from the African tropics, is sometimes sown in gardens in the state for its rapid growth and bold, striking colors.
PLANT CHARACTERISTICS: Castor bean is treated as an annual. It can grow to 5 m tall, The flowers are monoecious and without petals; stamens: very numerous, filaments much branched; ovarv: 3-celled; style: 3, each bifid and plumose, united at the base; fruit: a large, 3-lobed capsule covered with soft prickles; seeds: 1 cm long, mottled or streaked with white, red, or brown; leaves: alternate, large, simple, peltate, palmately veined, long petiolate, palmately 6- to 11-lobed; 1.4 dm wide.
POISONOUS PARTS: Seeds, and to a lesser extent foliage, are toxic; 1-3 seeds may be fatal to a child, 2-4, to an adult.
SYMPTOMS: There is often a lag time from initial ingestion until symptoms appear. Poisoning is indicated by gastrointestinal distress, burning mouth and throat, anorexia, nausea and vomiting, cramps, cessation of rumination, dullness, diarrhea, weakness, thirst. prostration, dullness of vision. convulsion, muscle spasm, uremia, and death. The digestive tract displays inflammation and punctiform hemorrhage of the mucosal lining. Organ damage includes fluid-filled lungs, and edematous and swollen liver and kidneys. In horses trembling, sweating, and incoordination may precede other symptoms, accompanied by unusually vigorous heart contractions and weak, rapid pulse. Cattle may display blood-stained diarrhea; pigs vomit profusely. In poultry egg production ends, molting commences, wattles and combs discolor, and the birds appear depressed.
Postmortem: gross lesions: mesenteric lymph nodes are edematous; histological lesions: necrosis of epithelium of affected gastrointestines; hydropic degeneration, fatty change, and necrosis of hepatocytes; renal epithelium experiences fatty degeneration and necrosis; marked destruction of lymphocytes in lymphoid organs; brain necrosis; in horses edema (pulmonary, bronchial, mesenteric, and hepatic lymph node).
POISONOUS PRINCIPLES: The highly toxic glycoprotein ricin is responsible for poisoning. This phytotoxin, a composite of various amino acids, consists of a neutral alpha-chain capable of inhibiting protein synthesis and an acidic beta-chain, which functions as a carrier and moiety that binds the toxin to cell surface. Phytotoxins may act as antigens eliciting an antibody response.
CONFUSED TAXA: No other ornamental plants have the characteristics described above; castor bean is readily distinguishable.
SPECIES OF ANIMALS AFFECTED: Humans are susceptible to this highly active poison. Seed amounts necessary for poisoning depend on the age of victim and amount of seed masticated since chewing enhances liberation of the toxin.
TREATMENT: Immediate (11a)(b); (26); (13 by administering 5-15 gm sodium bicarbonate daily)