types of habitats except for the sandy coastline. Despite being
a tree of immense proportions, Buchenavia remained undetected
amid the flora of Manuel Antonio National Park until 1990, when
it was discovered and recognized as a new species. Now also known
from the Osa Peninsula, its range is restricted to southwestern
Costa Rica. Description: Buchenavia has a massive, straight trunk (1.5 m or more) that initially is somewhat angular and prismatic but that becomes more cylindrical with height. It's base is surrounded by tall (2 m), thin, sheet-like buttresses that radiate outwards for up to three meters before sinking into the soil. The unlikely trunk shape produced by their great number, large size, thinness, and often parallel arrangement is often stunning. Buchenavia bark is light gray and characteristically grooved by narrow and dark vertical fissuring. Branching is confined to the extreme upper portion of the tree, where massive limbs spread out horizontally for tens of meters. They create a single-layered, umbrella-like or flat-toped crown of great diameter that shades a large swath of the forest floor beneath it. Mature specimens of this species are indeed commanding, evoking awe from all who behold them - certainly Buchenavia is among the most superlative of Costa Rican trees. As the branches successively subdivide, they form a series of upwardly-curving, concave arcs that decrease in diameter as they cascade toward the edges of the crown. Leaves are then borne in whorl-like clusters around the widened tips of the thin, curved twigs. Each leaf (9 by 3.5 cm) is simple, alternate, and long-petioled (2.5 cm). Smooth and light green, they are tear-drop shaped (obovate) - with rounded apices and tapered bases. Trees start loosing leaves slowly in late September and then more rapidly in October. From November to mid-December, the crowns are usually completely bare. By the end of the year, new leaves have begun to expand rapidly and the fresh, yellow-green foliage cover is complete by early January. Simultaneous with,
or
slightly preceding leaf production, is the appearance of many
stringy flower racemes. Each long, dangling raceme (14
cm) bears about 35 minute flowers (3 mm in diameter). The petal-less
blossoms consist only of a yellow, star-shaped, five-point calyx,
10 short stamens, and a central pistil. Faintly aromatic, they
emit a sweet and fruity fragrance. Buchenavia's annual
flowering period is exceedingly brief, prolific, precisely timed
(from season to season), and well synchronized. It occurs between
late December and early January with individual trees maintaining
open flowers for only about 10 days. Fruits begin to grow
immediately, slowly developing over the course of about eight
months - with the abortion of small fruits occurring continuously
throughout this time. They mature as globular or semi-globular
(2.5 cm), glossy yellow drupes contoured with longitudinal, pumpkin-like
ridges. The stiff flesh is filled with a sweet-smelling, fruity
sap and it covers one fibrous, almond-shaped seed (1.5-2.0 cm).
Ripe fruits hang vertically from the old flower raceme stalks,
resembling yellow Christmas ornaments nestled amid the green foliage
of the canopy. Harvests are annual and extended events, with the
yellow fruits slowly falling from the trees from late July through
early November. Seeds begin germinating a few weeks after fruit-fall,
the first seedlings appearing on the forest floor in August. They
emerge with their seed-leaves furled - a characteristic common
to many species of the Combretaceae family - resembling smaller
versions of Almendro seedlings.
observed to fall from the crown
and rot under the parent tree - with no effective dispersal agent
apparent. Possibly, the seeds are dispersed by mammal species
no longer present among the Manuel Antonio fauna - with spider
monkeys being particularly likely candidates. The young, tender
seedlings are frequently browsed by ground-dwelling lizards.
