''Enterolobium cyclocarpum'', commonly known as guanacaste, caro caro, monkey-ear tree, or elephant-ear tree, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

flowering A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

in the

pea The pea is most commonly the small spherical seed or the seed-pod of the flowering plant species ''Pisum sativum''. Each pod contains several peas, which can be green or yellow. Botanically, pea pods are fruit, since they contain seeds and d ...

family,

Fabaceae The Fabaceae or Leguminosae,International Code of Nomenc ...

, that is native to

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

regions of the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

, from central Mexico south to northern Brazil (

Roraima Roraima (, ) is one of the 26 states of Brazil. Located in the country's North Region, it is the northernmost and most geographically and logistically isolated state in Brazil. It is bordered by the state of Pará to the southeast, Amazonas ...

) and

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

. It is known for its large proportions, expansive, often spherical crown, and curiously shaped seedpods. The abundance of this tree, especially in

Guanacaste Province Guanacaste () is a province of Costa Rica located in the northwestern region of the country, along the coast of the Pacific Ocean. It is bordered by Nicaragua to the north, Alajuela Province to the east, and Puntarenas Province to the southeast. I ...

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

, where it is prized for the shady relief it provides from the intense sun, coupled with its immensity, have made it a widely recognized species. It is the

national tree This is a list of national trees, most official, but some unofficial. National trees See also * National emblem * Floral emblem * List of U.S. State and territory trees References {{DEFAULTSORT:List Of National Trees N Trees In b ...

of Costa Rica. In North America, it is often called elephant-ear tree, due to the shape of the seedpods. Other common names include devil's ear and earpod tree, ''parota'', and ''orejón'' (Spanish) orhuanacaxtle'' (

Nahuatl Nahuatl (; ), Aztec, or Mexicano is a language or, by some definitions, a group of languages of the Uto-Aztecan language family. Varieties of Nahuatl are spoken by about Nahua peoples, most of whom live mainly in Central Mexico and have smaller ...

). In

El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south b ...

, it is known as ''conacaste''. In the Yucatán peninsula, it is known by the Mayan name, ''pich.'' In Panama, it is known as a ''corotú''.

Description

The guanacaste is a medium-sized to large

, growing to tall, with a trunk up to in diameter. Unusual in a tree of these proportions, buttresses are completely lacking. The

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, ...

is light gray, with prominent dark reddish-brown, vertical fissures. In young trees, these fissures are closer together. and their confluence lends a characteristic reddish hue to the bark of guanacaste saplings. Older specimens often present broken, chipped, or scarred bark. The crown is broad and widely spreading. The height at which branches first occur along the trunk – as well as the overall tree shape – vary considerably among individuals and are habitat-dependent characteristics. Frequently, guanacaste trees grow as single specimens in a sunny pasture. Under these conditions, massive, extended, horizontal limbs emerge low on the boles, forming giant, hemispherical, widely spreading crowns. In the forest (where competition for light is intense), trees tend to become taller, and branching occurs at a higher level. Tree forms then become somewhat narrower, though crowns are still rounded, and hemispherical shapes are maintained by those that have reached the canopy. The alternate

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are bipinnate compound, long and broad with a petiole bearing four to 15 pairs of pinnae, each pinna with 40–70 leaflets; the leaflets are slender, oblong, long by wide. Near its base, the twiggy petiole bares a small, raised, oval gland. The leaves are confined to the outer shell of the crown, yet they are plentiful enough to make it moderately dense and green. The guanacaste is

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

, or briefly

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

for 1–2 months during the

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The te ...

. Most foliage is shed in December, at the start of the dry season. In late February, a growth surge is initiated that re-establishes a fresh, thick crown by April. Concurrent with the leaves' renewal is the appearance of globular

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

s () in the axils of the new leaves. Supported by a long pedestal (), each spherical white head – composed of about 50 individual flowers – sports thousands of thin, filamentous stamens as its major feature. The blossoms themselves each consist of about 20 stamens and a single pistil, bound together at the base by a short, green, tubular corolla and an even shorter calyx, just long altogether. Guanacaste flowers are very fragrant, and during intense flowering periods, their odor permeates the air for many meters in all directions. In Manuel Antonio National Park near Quepos, Costa Rica, flowering lasts from late February to early April. Surprisingly, no obvious fruiting activity immediately follows the decline of the blossom. Rather, 9-10 months pass before small, green pods first appear high in the crown by December. They reach full size by February and finally begin to ripen in March – a full year after flowering has ceased. Fruit ripening lasts from March to April, as the green pods turn brown in the guanacaste crown and are slowly shed. Vigorous trees produce large crops on a nearly annual basis. In June, guanacaste seedlings can already be seen, germinating in the moist soil of the early rainy season. Guanacaste fruits are large ( diameter), glossy dark brown

indehiscent Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...

and spirally organized pods, shaped like orbicular disks. Their shape suggests the usual

Mimosoideae The Mimosoideae are a traditional subfamily of trees, herbs, lianas, and shrubs in the pea family (Fabaceae) that mostly grow in tropical and subtropical climates. They are typically characterized by having radially symmetric flowers, with petals ...

fruit – a long, narrow, flattened pod – taken and wound around an axis perpendicular to its plane. Made of thick, soft tissue with a leathery feel, the pods contain eight to 20 radially arranged seeds, long, wide, and thick and weighing about 1 g. Guanacaste seeds are brown and marked with a conspicuous light brown or orange ring. They are very hard, resembling small stones rather than tree seeds in their strength and durability. For germination to occur, the hard seed coat must be broken to enable water to reach the embryo. Otherwise, the seeds lie dormant indefinitely. The ardillo (''

Cojoba arborea ''Cojoba arborea'' (common names include algarrobo, ardillo, lorito, barba de jolote, iguano, quebracho, sang sang, tamarindo, tambrán, tuburús, and bahamas sibicú) is a leguminous tree of the family Fabaceae found in the Caribbean, Mexico, a ...

'') and the iguano (''

Dilodendron costaricense ''Dilodendron'' is a genus of flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vesse ...

'') possess similar bipinnate leaves with extra-fine leaflets. Though of equally impressive stature, these two trees can be distinguished readily from the guanacaste; the ardillo has tan-colored, heavily wrinkled, and rough bark – nothing like the guanacaste's unmistakably gray and vertically cracked cortex. The iguano's leaflets are serrated (an unusual feature in a bipinnate tree), while those of the guanacaste are entire.

Ecology

Guanacaste trees appear to delay the onset of fruit development—some 9 months—so that seed maturation coincides with the start of the rainy season. This adaptive behavior presumably is an adaptation to give germinating seedlings as much time as possible to establish root systems before the start of the next dry season. Both the jatobá (''Hymenaea courbaril'') and the cenizaro (''

Albizia saman ''Samanea saman'', also sometimes known as the rain tree, is a species of flowering tree in the pea family, Fabaceae, now in the Mimosoid clade and is native to Central and South America. Its range extends from Mexico south to Peru and Brazil, ...

'') exhibit similar reproductive strategies. Of course, guanacaste trees—like all

and

semideciduous Semi-deciduous or semi-evergreen is a botanical term which refers to plants that lose their foliage for a very short period, when old leaves fall off and new foliage growth is starting. This phenomenon occurs in tropical and sub-tropical woody spe ...

species in this part of the world—share in the water-conserving benefits of dry-season leaflessness. Guanacaste flowers are heavily visited by

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...

s—insects that probably are responsible for pollination, as well. Guanacaste seed pods, however, are completely ignored by native fauna and they accumulate on the forest floor underneath parent trees. The seeds are not eaten by any animals currently native where the tree occurs, rendering the plant an

evolutionary anachronism Evolutionary anachronism is a concept in evolutionary biology named by Connie C. Barlow in her book, ''The Ghosts of Evolution'' (2000). It refers to attributes of living species that are best explained as a result of having been favorably select ...

: it has been suggested that guanacaste pods were among the foods exploited by certain species of

Pleistocene megafauna Pleistocene megafauna is the set of large animals that lived on Earth during the Pleistocene epoch. Pleistocene megafauna became extinct during the Quaternary extinction event resulting in substantial changes to ecosystems globally. The role of hu ...

that became

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

some 10,000 years ago (e.g.

giant ground sloths ''Megatherium'' ( ; from Greek () 'great' + () 'beast') is an extinct genus of ground sloths endemic to South America that lived from the Early Pliocene through the end of the Pleistocene. It is best known for the elephant-sized type species ' ...

giant bison ''Bison latifrons'', also known as the giant bison or long-horned bison, is an extinct species of bison that lived in North America during the Pleistocene epoch ranging from Alaska to Mexico. It was the largest and heaviest bovid ever to live in ...

). Within this scenario, the tree remains today without an effective seed-dispersing vector besides humans. As discussed above, the tough-coated guanacaste seeds do not begin to grow unless their protective covers are punctured in some way. This may be an adaptation designed to keep the seeds from germinating while still in the pods at the start of the

rainy season The rainy season is the time of year when most of a region's average annual rainfall occurs. Rainy Season may also refer to: * ''Rainy Season'' (short story), a 1989 short horror story by Stephen King * "Rainy Season", a 2018 song by Monni * ''T ...

—and very likely still underneath the parent tree after having fallen from its crown. With more time to find them, foraging ground sloths (and other extinct mammals) could eat the pods and transport the seeds to a new site. The resulting mastication and digestion of the fruits would induce seed coat abrasion, which would help seed germination. Nowadays this role of mastication and dispersal has been taken up primarily by

horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...

and

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...

. An insect pest, common to guanacaste trees of the

Costa Rican Central Valley The Central Valley () is a plateau and a geographic region of central Costa Rica. The land in the valley is a relative plain, despite being surrounded by several mountains and volcanoes, the latter part of the Central Range. The region houses al ...

, produces spherical green

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

s of diameter on new shoots in February and March. Similar parasitism seems to occur on guanacaste trees of the wet, southwestern lowlands (around

Palmar Sur Palmar Sur is a town in Costa Rica, located next to Palmar Norte in the Osa region of Puntarenas Province of Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), ...

Cultivation and uses

The guanacaste is among the most majestic and aesthetically pleasing of tree species in its native range. Tolerant of a wide range of rainfall levels, temperatures, and soil conditions, they can thrive in most low-elevation, tropical habitats. Guanacaste trees are highly valued as ornamentals, and the shade they provide creates many an oasis on the searing and sun-baked plains in its Pacific slope habitat. It is widely grown as a shade tree to shelter

coffee Coffee is a drink prepared from roasted coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulant, stimulating effect on humans, primarily due to its caffeine content. It is the most popular hot drink in the world. S ...

plantation A plantation is an agricultural estate, generally centered on a plantation house, meant for farming that specializes in cash crops, usually mainly planted with a single crop, with perhaps ancillary areas for vegetables for eating and so on. The ...

s and for shade and

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...

for cattle; it also improves soil fertility by

nitrogen fixation Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmo ...

.Niembro Rocas (2002) The guanacaste is found in

USDA The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...

Growth Zones 10–12. The

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...

is reddish-brown, lightweight (density ) and water-resistant; it is used to make items such as doors, windows, furniture, and cabinets, and for shipbuilding. It is considered a relatively sustainable resource for wooden furniture and design projects, largely due to the tree's ability to quickly reach large sizes, which also makes it easier to find large natural cuts up to several meters, which is rare for other slower-growing woods, such as oak or cedar. The town of

La Cruz de Huanacaxtle ''La Cruz de Huanacaxtle'' ("The Cross of Huanacaxtle") is a Mexican fishing village situated on the Pacific Ocean's Bahía de Banderas in the state of Nayarit. It is situated approximately 25 km from Puerto Vallarta, Jalisco Jalisco (, ...

Nayarit Nayarit (), officially the Free and Sovereign State of Nayarit ( es, Estado Libre y Soberano de Nayarit), is one of the 31 states that, along with Mexico City, comprise the Federal Entities of Mexico. It is divided in 20 municipalities and its ...

(Mexico) derives its name from the fact that a cross used to stand there made of guanacaste wood. While the seed pods are still green, they are harvested and the seeds eaten boiled in Mexico. Healthy guanacaste trees generate massive, nearly annual crops of seeds. The attractive seeds are used in Costa Rica to make jewelry. In parts of Panama, the ripe seeds are heated in a fire until they pop like popcorn. These seeds demonstrate germination rates of nearly 100%. Guanacaste seedlings then grow rapidly, often reaching over in height in their first year. These aggressive reproductive characteristics might be beneficially exploited in

reforestation Reforestation (occasionally, reafforestation) is the natural or intentional restocking of existing forests and woodlands (forestation) that have been depleted, usually through deforestation, but also after clearcutting. Management A debate ...

projects, though the plant is considered an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

in some places. Its roots are strong, and those of large trees may damage nearby structures. Guanacaste is commonly used to feed all kind of livestock; its foliage, fruits, and seeds are relished by cattle, pigs, goats, sheep, and horses. The parota tree is believed to provide medical benefits. In Mexican folk medicine, the sap is thought to aid illnesses such as influenza and bronchitis, while the astringent properties of its green fruit are used for diarrhea. The fruit and bark also contain tannins, which are useful for leather curing and soap manufacturing, while the sap can be used as a natural adhesive or substitute for glue, or chewed as a type of gum.

Synonyms

The guanacaste has in the past been referred to by these

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

s:ILDIS (2005) * ''

Albizia ''Albizia'' is a genus of more than 160 species of mostly fast-growing subtropical and tropical trees and shrubs in the subfamily Mimosoideae of the family Fabaceae. The genus is pantropical, occurring in Asia, Africa, Madagascar, America and A ...

longipes'' Britton & Killip * ''Enterolobium cyclocarpa'' (Jacq.) Griseb. (''

lapsus In philology, a lapsus (Latin for "lapse, slip, error") is an involuntary mistake made while writing or speaking. Investigations In 1895 an investigation into verbal slips was undertaken by a philologist and a psychologist, Rudolf Meringer and K ...

'') * '' Feuilleea cyclocarpa'' (Jacq.) Kuntze * ''

Inga ''Inga'' is a genus of small tropical, tough-leaved, nitrogen-fixing treesElkan, Daniel. "Slash-and-burn farming has become a major threat to the world's rainforest" ''The Guardian'' 21 April 2004 and shrubs, subfamily Mimosoideae. ''Inga''s l ...

cyclocarpa'' (Jacq.) Willd. :Not to be confused with ''

Inga cyclocarpa ''Inga'' is a genus of small tropical, tough-leaved, nitrogen-fixing treesElkan, Daniel. "Slash-and-burn farming has become a major threat to the world's rainforest" ''The Guardian'' 21 April 2004 and shrubs, subfamily Mimosoideae. ''Inga''s l ...

'' Ducke * ''

Mimosa ''Mimosa'' is a genus of about 590 species of herbs and shrubs, in the mimosoid clade of the legume family Fabaceae. The generic name is derived from the Greek word (''mimos''), an "actor" or "mime", and the feminine suffix -''osa'', "resembl ...

cyclocarpa'' Jacq. * ''Mimosa parota'' Sessé & Moc. * ''

Pithecellobium ''Pithecellobium'' is a genus of flowering plants in the family Fabaceae. The generic name is derived from the Greek words πίθηκος (''pithêkos''), meaning "ape" or "monkey," and ἐλλόβιον (''ellobion''), meaning "earring," which r ...

cyclocarpum'' (Jacq.) Mart. * ''

Prosopis ''Prosopis'' is a genus of flowering plants in the family Fabaceae. It contains around 45 species of spiny trees and shrubs found in subtropical and tropical regions of the Americas, Africa, Western Asia, and South Asia. They often thrive in ari ...

dubia'' Kunth

Description

Ecology

Cultivation and uses

Synonyms

References

Further reading