Hibiscus pernambucensis Arruda (= H. tiliaceus L.)
Malvaceae AMAPOLA DE LA PLAYA
Occasional evergreen treelet or shrub (2-6 m) found growing exclusively along the vegetated fringes of sandy beaches. These easily recognizable plants have heart-shaped leaves and showy yellow flowers. They often represent the front lines in the vegetative struggle to exploit the sunny but otherwise severe conditions of the salty, coastal zone.
Description: The shifting sands and high winds of the open coastline take their toll on the rugged plants that try to live there. More often than not, Amapola trees are broken and bent, forming haphazard – almost vine-like – tangles of trunks and branches nearly at the water’s edge. Boles thicken to about 30 cm in diameter and are covered with gray-brown bark that is streaked with darker vertical fissures. Tough fibers within the bark give it – and the branches – great strength. Thin and wiry, Amapola limbs narrow into extremely flexible, whip-like twigs. The large, simple, alternate leaves (17 cm blade on a 13 cm petiole) are heart-shaped (cordate) and leathery. A fine pubescence coats leaf undersurfaces, petioles and twigs. Opaque and tan-colored, this covering creates blade faces of contrasting green and tan hues.
Flowers, typical of the showy Hibiscus genus, are large (8 cm in diameter), brightly colored, and attractive. The perianth consists of five pubescent green sepals and an equal number of strongly-veined, spirally-arranged, yellow petals. Many short stamens crowd theouter surface of a tube that lies along the flower’s radial axis and through which a long pistil passes. Interestingly, blossoms change color during the course of their one-day life, slowly grading from yellow, through orange to red before they finally die and are shed. Flowering is nearly a year-long event, experiencing a brief hiatus only during the core of the dry season (February and March). Held within the persistent calyx, fruits are dry capsules (2 cm) that open into five, wedge-shaped sections. Each hollow capsule segment is divided by a thin, papery wall to which are attached several hard, brown, rounded seeds (3 mm in diameter). Harvests also continue nearly year round.
Similar Species: There are no other species present along the immediate coastline that share Amapola’s leaf shape. Furthermore, its exclusive, beach-side habitat – one that is tolerated by few other plants – makes it relatively easy to isolate and identify.
Natural History: Positioned at the dividing line between the relatively dark forest interior and the brilliantly lit, sandy beach, Amapola trees have evolved a peculiar growth strategy – one that they share with at least two other beachside species (Terminalia catappa and Hippomane mancinella). Unable to root too close to the high water line, Amapola trunks grow outward from the vegetated coastal fringe toward the ocean.As they do this, their crowns reach areas of high insolation but their stems become inclined and unstable. Sometimes, these remarkable boles remain aloft, growing parallel to the beach and only a meter or two above its surface. More usually, however, they topple – unbalanced and poorly anchored in the sandy substrate. Adapted to this way of life, fallen Apapola’s rarely die. Instead, sprawled out over the beach and in the bright sunshine, new shoots and branches emerge. Tough fibers found in Amapola bark serve to bind limbs and trunks together, often keeping them from severing completely under these adverse circumstances. After many years of such growth, complex tree forms result, giving Amapola (and to a lesser extent Terminalia and Hippomane) a confused, tangled, and haphazard appearance.
Amapola flowers are pollinated by long-billed hummingbirds. Their dry fruits contain bare seeds that appear to lack any effective means of dispersal: seeds merely drop to the sand underneath the parent plants. Since Amapola crowns are usually positioned near the upper limit of the littoral zone, it is conceivable that the seeds are transported along the shoreline by sea water.
Uses: Tough and resilient, the fibers found within Amapola bark have been used for making strong rope and twine. The hardiness of this tree, including its ability to withstand harsh, salt-laden conditions, make it a good candidate for the control of beach erosion. Finally, Allen (1956) reports that the wood of this species is white, light, straight-grained and easy to work, but that it has not been exploited.
Distribution: Amapola de la Playa is found along Costa Rica’s Pacific and Caribbean coasts. Apparently, it is native to Asia, having been transplanted and naturalized in the Americas, where it now grows wild throughout the Neotropics.
Trees of Costa Rica's Pacific Slope 
