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''Enterolobium cyclocarpum'', commonly known as guanacaste, caro caro, or elephant-ear tree, is a species of flowering tree in the pea family, Fabaceae, that is native to tropical regions of the Americas, from central Mexico south to northern Brazil (Roraima) and Venezuela.〔USDA (1994), Niembro Rocas (2002)〕 It is known for its large proportions, its expansive, often spherical crown, and its curiously shaped seedpods. The abundance of this tree, especially in Guanacaste Province, Costa Rica, 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 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) or ''huanacaxtle'' (Nahuatl). In El Salvador, it is known as ''conacaste''.〔Witsberger ''et al.'' (1982)〕 ==Description〔Niembro Rocas (2002), Harmon (2008), PIER (2008)〕== The guanacaste is a medium-sized to large tree, growing to 25–35 m tall, with a trunk up to 3.5 m in diameter. Unusual in a tree of these proportions, buttresses are completely lacking. The bark 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 are bipinnate compound, 15–40 cm long and 17 cm broad with a 2–6 cm petiole bearing 4–15 pairs of pinnae, each pinna with 40–70 leaflets; the leaflets are slender oblong, 8–15 mm long by 2–4 mm 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, or briefly deciduous for 1–2 months during the dry season. 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 inflorescences (3 cm) in the axils of the new leaves. Supported by a long pedestal (4 cm), each spherical white head - composed of about fifty individual flowers - sports thousands of thin, filamentous stamens as its major feature. The blossoms themselves each consist of about twenty stamens and a single pistil, bound together at the base by a short, green, tubular corolla and an even shorter calyx, just 5 mm 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, nine or ten 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 will 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 (7–12 cm diameter), glossy dark brown indehiscent and spirally-organized pods, shaped like orbicular disks. Their shape suggests the usual Mimosoideae 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 8-20 radially arranged seeds, 14.5–17.5 mm long, 7.8–11.2 mm wide, and 6.2–7.2 mm 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. In order for germination to occur, the hard seed coat must be broken to enable water to reach the embryo. Otherwise, the seeds will lie dormant indefinitely. The ardillo (''Cojoba arborea'') and the iguano (''Dilodendron costaricense'') 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 serrate (an unusual feature in a bipinnate tree), while those of the guanacaste are entire. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Enterolobium cyclocarpum」の詳細全文を読む スポンサード リンク
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