Gymnocladus dioica (L.) C. Koch—Kentucky coffee-tree
FAMILY: Caesalpiniaceae—the Caesalpina Family
The bean family, Leguminosae, is naturally divided into three subfamilies: the Faboideae, the Mimosoideae, and the Caesalpinioideae. Some authorities classify the three subfamilies as separate families as they are presented here. The Fabaceae family description is found under the Crotaiaria entry. No members of the Mimosaceae found within Pennsylvania are toxic. The Caesalpiniaceae are characterized by flowers: perfect or unisexual, regular or sometimes irregular; hypanthium: well developed, often irregular; sepals: 5; petals: 1-5; stamens: typically twice as many as the sepals; ovary: 1; fruit: a legume splitting along 2 sutures.
PHENOLOGY: Gymnocladus dioica flowers in May.
DISTRIBUTION: Kentucky coffee-tree is found in rich moist woods. It is seldom abundant, frequently occurring as single trees.
PLANT CHARACTERISTICS: Kentucky coffee-tree is a tall tree, to 30 m; plants: bear on one tree flowers partly perfect and partly pistillate, and on another tree flowers partly perfect and partly staminate; flowers: regular, perfect or unisexual, 5-merous; hypanthium: tubular, 10-15 mm; sepals and petals in a single series, 8-10 mm; stamens: 10, distinct, alternately long and short; fruit: red-brown, woody, flat. thick, often exuding a yellow resin when broken; seeds: few per pod, large, separated by pulp; branches: stout, without small twigs or thorns; leaves: very large, bipinnately compound, new leaves often pink; leaflets: 2-3 cm wide; inflorescence: terminal panicles of greenish-white flowers.
POISONOUS PARTS: The sprouts, foliage, and fruit are poisonous.
SYMPTOMS: Severe gastrointestinal irritation and narcotic-like effects on the nervous system have been reporte. Postmortem: gross and histological lesions: congestion of the mucous membranes.
POISONOUS PRINCIPLES: The cause of toxicosis is unknown but may be due to the presence of alkaloids. Cytisine, a toxic quinolizidine alkaloid, has been extracted from leaves, pods, and seeds. The LD50 orally in mice is 50-101 mg/kg, subcutaneous in dogs it is 4 mg/kg body weight.
CONFUSED TAXA: The bipinnate leaves of Kentucky coffee-tree may be confused with the bipinnate or even-pinnate leaves of honey locust (Gleditsia triacanthos L.), also in the Caesalpinaceae. Honey locust has leaflets 1 cm wide, thorns that may be branched, and flowers in spike-like racemes. The pulp of the honey locust fruit is sweet-tasting and nonpoisonous.
SPECIES OF ANIMALS AFFECTED: Kentucky coffee-tree is poisonous for apparently all classes of livestock and for humans.
TREATMENT: (11a)(b); (26)
OF INTEREST: A case exists of a woman who was poisoned after eating some fruit pulp of Kentucky coffee-tree, mistaking it for honey locust. Cases have been cited in which death occurred in sheep in less than 1 day after the appearance of symptoms. Seeds of this plant have been used for a coffee substitute.
The golden chain tree, Laburnum anagyroides Medic., a cytisine- producing legume in the Fabaceae, can cause toxicosis as well. This widely cultivated tree with long-petioled, trifoliate, alternate leaves produces hanging racemes, about 5 dm long, of golden-yellow flowers. The fruit is a legume pod containing up to 8 seeds. The seeds and flowers, eaten in large quantities, can produce poisoning characterized by excitement, gastroenteritis, dilation of pupils, incoordination, irregular pulse, convulsions, coma, and death through asphyxiation. Oral toxicity of seeds for horses is about 0.05% of the animal's weight. Treatment: (11a)(b); (26); (1); (6).