Calathea lancifolia (rattlesnake plant) is a species  of flowering plant in the Marantaceae family,ntive to Brazil. Requiring a minimum temperature of 16 °C (61 °F), it is commonly used as a houseplant in temperate regions.

It is an evergreen perennial, growing to 60–75 cm (24–30 in), with slender pale green leaves to 45 cm (18 in), heavily marked above with dark blotches, purple below.*

*References: Wikipedia