any of several closely related species of the genus Lobelia, perennial plants of the family Campanulaceae that are native to North and Central America. All bear spikes of scarlet, lipped flowers on leafy stems up to 1.5 metres (5 feet) tall. L. cardinalis and L. splendens, considered to be one species by some authorities, are taller than L. fulgens, the Central American parent species of the garden cardinal flower. The blue cardinal (L. siphilitica) is smaller than the others and has blue or whitish flowers.