Sea Heart

Entada gigas is native to the tropical forests of Central and South America.

• Distributed from southern Mexico through Central America to Colombia, Venezuela, the Guianas, Ecuador, Peru, and Brazil
• Found in lowland tropical rainforests, secondary forests, and forest margins
• Occurs from sea level to approximately 600 m elevation
• The vine is most common near rivers and coastal areas where seed dispersal by ocean currents is possible
• Seeds have been found on beaches in the Azores, Canary Islands, Ireland, Scotland, Norway, and even as far as Iceland
• First described by the German botanist Johann Heinrich Friedrich Link
• Related to Entada phaseoloides of the Old World tropics, which also produces large drift seeds
• The legendary "sea beans" found on European beaches were once attributed to mythical underwater trees

A massive, woody tropical liana (climbing vine).

Stem:
• Main stem is woody, thick, flattened or ribbon-like, up to 5-10 cm wide
• Climbs by twining around host trees, reaching 20-30 m into the canopy
• Older stems develop thick, fissured, dark brown bark
• The vine is one of the most massive climbers in Neotropical forests

Leaves:
• Twice-pinnately compound (bipinnate), 20-40 cm long
• Each leaf has 2-4 pairs of pinnae, each bearing 3-5 pairs of leaflets
• Leaflets are oblong-elliptic, 5-10 cm long and 2-4 cm wide
• Dark glossy green above, paler beneath
• Petioles are winged with a glandular swelling near the base

Flowers:
• Small, creamy-white to pale yellow, arranged in dense, cylindrical spikes 5-10 cm long
• Individual flowers are about 3-5 mm long
• Flowers are mildly fragrant
• Multiple spikes are arranged in large, branched panicles at branch ends
• Pollinated by insects, particularly bees and wasps

Fruit and Seeds:
• The most distinctive feature: enormous, woody, flattened legume pods 60-200 cm long and 8-12 cm wide
• Pods are dark brown, woody, and segmented, each segment containing a single seed
• Pods split open while still attached to the vine, releasing seeds that fall to the forest floor or into rivers
• Seeds: large, flat, glossy, dark brown, perfectly heart-shaped, 4-6 cm in diameter
• Seeds have an extremely hard, water-resistant seed coat enabling oceanic drift

Sea Heart is a spectacular component of Neotropical rainforest canopy ecosystems.

• A canopy-dominant liana that plays a major structural role connecting tree crowns
• Massive vines create "highways" through the canopy used by arboreal animals
• Flowers provide nectar for diverse insect communities
• Seeds are among the longest-distance naturally dispersed plant propagules on Earth
• Oceanic drift seeds can travel thousands of kilometers on ocean currents, remaining viable for 1-2 years
• The extraordinarily hard seed coat prevents waterlogging and protects the embryo during long ocean voyages
• Seeds that reach distant shores rarely find suitable conditions for germination and establishment
• In native forests, seeds are predated by bruchid beetles that bore into the seed coat
• The vine's massive weight can bring down weakened canopy trees
• Provides important habitat structure for canopy-dwelling birds, reptiles, and amphibians

Sea Heart seeds are among the easiest tropical plants to germinate.

• Seeds are famously durable and can be stored for years before planting
• Germination requires nicking or filing through the extremely hard seed coat (scarification)
• After scarification, seeds swell dramatically when soaked in warm water for 24-48 hours
• Germination occurs within 7-14 days after soaking
• Plant in deep, well-draining, fertile soil in a warm, humid location
• Requires tropical conditions with temperatures above 20°C
• Full sun to partial shade; seedlings benefit from some shade
• Growth is extremely rapid once established, sending out long climbing stems
• Requires a strong support structure (large trellis, pergola, or tree) for the massive vine
• Consistent moisture is essential for optimal growth
• Can be grown as a novelty container plant when young, showcasing the enormous seeds
• Not suitable for temperate outdoor cultivation