Blue Ash - Blue Ash

A deciduous tree of the family Oleaceae (APG classification: Oleaceae). It is also called fraxinus kobanotoneriko. The leaves are pinnately compound with 5-7 leaflets, which are opposite and oblong, 5-10 cm long, pointed at the tip, and have low serrated edges. In April and May, many small white flowers bloom in panicles at the ends of the branches, with male and bisexual flowers on separate plants. The petals are thin and four separate, and each bisexual flower has one pistil and two stamens. The fruits are oblanceolate, 2.5-3 cm long samaras, and ripen in October. They commonly grow in mountainous areas, and are distributed in Hokkaido, Honshu, Shikoku, Kyushu, the southern Kuril Islands, and southern Korea. Those with hairless branches, winter buds, leaves, and inflorescences are sometimes called Aodamo, while those with coarse hairs are called Arage Aodamo. The "Ao" in Aodamo is said to come from the fact that when the branches are cut and placed in water, the water emits a blue fluorescence, and "Tamo" is a local name for the ash tree. Both the sapwood and heartwood are pale brown-yellow, and because it is hard and tough, it is used for baseball bats, racket frames, and other equipment.

[Yoshio Kobayashi July 16, 2021]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

モクセイ科（APG分類：モクセイ科）の落葉小高木。コバノトネリコともいう。葉は対生し、小葉が5～7枚ある羽状複葉で、小葉は長楕円(ちょうだえん)形、長さ5～10センチメートルで先がとがり、縁(へり)に低い鋸歯(きょし)がある。4～5月、枝先に円錐(えんすい)花序になって細かい白色花が多数開き、雄花と両性花が別株につく。花弁は細く、4枚が離生し、両性花には雌しべ1本と雄しべ2本がある。果実は倒披針(とうひしん)形、長さ2.5～3センチメートルの翼果で、10月に熟す。山地に普通に生え、北海道、本州、四国、九州、千島南部、朝鮮南部に分布する。枝や冬芽、葉、花序などが無毛のものをアオダモ、粗毛のあるものをアラゲアオダモといって分けることがある。アオダモの「アオ」は、枝を切って水につけると水が青色の蛍光を発するためといわれ、「タモ」はトネリコの一地方名である。材は辺材、心材とも淡褐黄色で、堅くて粘りが強いため野球用バット、ラケット枠、器具類に用いる。

［小林義雄　2021年7月16日］

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