Lobelia cardinalis L.—Cardinal-flower
Lobelia inflata L —Indian tobacco
Lobelia spicata Lam.—Lobelia
FAMILY: Lobeliaceae—the Lobelia Family
Although this family is mainly tropical, several members occur in Pennsylvania. The plants contain acrid, milky sap; leaves: alternate, simple, entire. toothed or pinnately parted; calyx: Slobed; corolla: irregular, 2-lipped, 5-lobed, the tube split nearly to the base on one side; stamens: 5; anthers: united into a tube around the style; ovarv: inferior, 2- to S-celled; fruit: a capsule.
PHENOLOGY: Lobelias generally flower July through September.
DISTRIBUTION: Lobelias are found in wet soil, along streams, ponds, shores, and in swamps. They are also cultivated for garden use.
PLANT CHARACTERISTICS: In Lobelia the corolla is characteristically split to the base on the upper side; bilabiate, having 2 lobes above and below, the upper lobes erect, the lower lobes usually spread; stamens: protrude through the split in the corolla; the 2 lower stamens bearded at the tip; inflorescence: a terminal bracteate raceme, flowers alternately inserted; leaves: decurrent.
POISONOUS PARTS: All parts of Lobelia are poisonous. Lobelia is toxic to animals at 0.5% of body weight.
SYMPTOMS: Toxicosis develops within 3 days. In livestock, symptoms are sluggishness, salivation, diarrhea, anorexia, ulceration around the mouth, nasal discharges, and eventually coma. Also, lesions of hemorrhage and mild gastroenteritis may be present. In humans, symptoms include vomiting, sweating, pain, paralysis, depressed temperature, rapid but weak pulse, collapse, coma, and death.
POISONOUS PRINCIPLE: Toxins are pyridine alkaloids, especially lobeline.
CONFUSED TAXA: Lobelia cardinalis, a tall (I m) perennial of stream banks, produces red flowers in late summer. Lobelia inflata is a tall (to 1 m in moist ground, much less in dry habitats) annual, which produces pale blue to white flowers July through October, The hypanthium (calyxtube) is much inflated in fruit. Lobelia spicata is a perennial resembling L. inflata but not developing a bladder-like hypanthium. At least a dozen species and varieties of Lobelia are elements of Pennsylvania's flora. All should be considered poisonous, with perhaps L. inflata the most toxic. Cultivated taxa include L. erinus L. (edging lobelia), L. x Gerardii Chab, & Gonj, ex Sauv., L. siphilitica L, L. x speciosa Sweet, and L. tenuTor R. Br.
SPECIES OF ANIMALS AFFECTED: Humans and livestock are susceptible.
TREATMENT: (11a)(b); (26); (6) (5- at the rate of 2 mg IM as needed)
OF INTEREST: Lobelia inflata is the source of the alkaloid lobeline used medicinally as a respiratory stimulant and in veterinary science as a respiratory stimulant and ruminatonic.