Bombacopsis sessilis (Benth.)
Pittier
Common Name: PALO VERDE, CEIBA
Rare deciduous canopy tree (20-25m) found growing almost exclusively
in sandy soils and in near proximity to the ocean. Often forming
small stands, Palo Verde is an interesting tree for its unique
ecology, attractive leaves, and very limited range: it is endemic
to Panama and Costa Rica's southern Pacific coast.
Description: Palo Verde has a cylindrical,
though bent and often inclined trunk (60 cm). At its base,
the bole develops small but distinct buttress roots that meld
with it at a height of about one meter. Branches are relatively
few in number, stout, and haphazardly arranged, yielding a thin,
somewhat narrow, asymmetrical crown. Palo Verde's bark is green
to yellow in color, with prominent and extended vertical cracking.
Older bark turns gray and eventually exfoliates in narrow, thin
strips. The foliage is made up of palmately compound, alternate
leaves (23 cm long), each bearing approximately seven or
eight leaflets at the end of a long petiole (9 cm). Leaflets are
spatulate (wider distally and slowly tapering proximally), with
obcordate (indented) apices and smooth surfaces. 
They are arranged in a circle around their
common point of attachment to the petiole, forming an almost complete,
though asymmetrical, disk of leaf tissue. Of variable size, distally
placed leaflets are about twice as big (11 cm by 4 cm) as proximal
ones (6 cm by 3 cm). Old leaves senesce and are shed during December
and the trees remain bare until late February when leaf buds break
and new foliage begins to expand. Emerging like so many small
stars, the new leaves surround twig tips in a single horizontal
plane. Still thin, and translucent, sunlight filters through the
blades, making them glow with different pastel shades of pink,
orange, and green. The aesthetic harmony of color, form, and arrangement
is quite stunning. Trees are fully foliated by May. Palo Verde's
flowers are also unusual. They are produced at the ends
of the stubby, bare twigs and are composed of five, long (15 cm),
bicolored petals - divided longitudinally into green and maroon
halves. These curl back around the base of the flower and expose
an equally long bundle of about 200 white stamens surrounding
a central red pistil. Opening at night, Palo Verde blossoms release
a very sweet-smelling aroma. Flowers are present from mid-December
through mid-February. When they die, the accumulation of brown,
dried stamens and petals on otherwise leafless trees combine to
give them a brownish cast - making Palo Verde boles recognizable
from a distance (particularly when seen along the coast from the
water). Relatively few fruits develop from the many flowers
that bloom. Each is a brown, leathery pod (17 cm long by 5 cm
in diameter) containing tens of globular brown seeds (1 cm) embedded
in copious quantities of tan-colored cotton. When the pod dries
sufficiently, it opens and the outer husk falls to the ground,
leaving the seeds and cotton exposed and still clinging to the
branch. Over a period of days or weeks, the seeds are released
- each with its own individual cottony "parachute" -
as the wind tugs at and dislodges them. Harvests last from March
to early June. Germination of the seeds is immediate upon contact
with moist soil - or, if the weather is still dry, the arrival
of the rainy season.
Similar Species: Palmately compound
leaves are shared by many members of the Bombacaceae and Bignoniaceae
families. Tabebuia - of the latter family - is easy to
distinguish since its leaves are made up of only five leaflets
(see description). Barrigón (Pseudobombax septenatum)
and Ceiba (Ceiba pentandra), both of the Bombacaceae, have
leaflets in similar numbers to those of Palo Verde. Barrigón
has a greener trunk, and this coloration is broken into vertical
stripes that Bombacopsis lacks. The Ceiba tree grows to immense,
emergent proportions, and it is found in the deep forest - far
away from the coast - which is the only place the smaller Palo
Verde tree is found.
Natural History: As with most
Bombacaceae flowers, those of Palo Verde are pollinated at night
by bats and large moths, though bees can be observed visiting
them in large numbers during the day. Bombacopsis seeds are wind
dispersed. Their cottony parachutes cause them to fall more slowly,
allowing them to be carried longer distances by air currents.
Furthermore, once on the ground they act like small tumbleweeds,
gaining extra distance by rolling across the smooth and sandy
soil. The advantages inherent in dry season fruiting for a tree
that depends upon cotton for creating air resistance and maintaining
lightness are apparent.
Orange-chinned parakeets have been observed
searching through the cottony pods while still in the trees and
eating the seeds that they find. This parasitic behavior does
not aid in seed dispersal since the seeds thus consumed are usually
destroyed.
Bromeliads and other epiphytic plants are commonly found attached
to Palo Verde branches due to the openness of its crown and the
large amounts of insolation that penetrate it. This is even more
true during the dry season when no foliage is present to obstruct
the sun.
Palo Verde's green bark probably
enables it to continue doing photosynthesis during the dry season,
when leaves are not present. It shares this characteristic with
two other deciduous trees present in its habitat: Barrigón
(Pseudobombax septenatum) and Indio Desnudo (Bursera
simaruba).
Uses: Palo Verde's seeds are
edible (they are said to be especially good toasted). The cotton
found in the pods can be used as insulation or as a filler for
upholstery. As is the case with other Ceibas, Palo Verde wood
is light and not used.
Distribution: Palo Verde is generally
only found within the fringe of vegetation lining the beach. It
is protected in Costa Rica by Manuel Antonio and Corcovado National
Parks. Palo Verde ranges from southwestern Costa Rica (with populations
occurring as far north as Esterillos Oeste) to Panama.
Tree Fruit Flower Trunk
They are arranged in a circle around their
common point of attachment to the petiole, forming an almost complete,
though asymmetrical, disk of leaf tissue. Of variable size, distally
placed leaflets are about twice as big (11 cm by 4 cm) as proximal
ones (6 cm by 3 cm). Old leaves senesce and are shed during December
and the trees remain bare until late February when leaf buds break
and new foliage begins to expand. Emerging like so many small
stars, the new leaves surround twig tips in a single horizontal
plane. Still thin, and translucent, sunlight filters through the
blades, making them glow with different pastel shades of pink,
orange, and green. The aesthetic harmony of color, form, and arrangement
is quite stunning. Trees are fully foliated by May. Palo Verde's
flowers are also unusual. They are produced at the ends
of the stubby, bare twigs and are composed of five, long (15 cm),
bicolored petals - divided longitudinally into green and maroon
halves. These curl back around the base of the flower and expose
an equally long bundle of about 200 white stamens surrounding
a central red pistil. Opening at night, Palo Verde blossoms release
a very sweet-smelling aroma. Flowers are present from mid-December
through mid-February. When they die, the accumulation of brown,
dried stamens and petals on otherwise leafless trees combine to
give them a brownish cast - making Palo Verde boles recognizable
from a distance (particularly when seen along the coast from the
water). Relatively few fruits develop from the many flowers
that bloom. Each is a brown, leathery pod (17 cm long by 5 cm
in diameter) containing tens of globular brown seeds (1 cm) embedded
in copious quantities of tan-colored cotton. When the pod dries
sufficiently, it opens and the outer husk falls to the ground,
leaving the seeds and cotton exposed and still clinging to the
branch. Over a period of days or weeks, the seeds are released
- each with its own individual cottony "parachute" -
as the wind tugs at and dislodges them. Harvests last from March
to early June. Germination of the seeds is immediate upon contact
with moist soil - or, if the weather is still dry, the arrival
of the rainy season.
