ミツガシワの低地自生群は「氷河遺存植物」。湿原に咲く花は透き通るような白色、糸状突起の縁飾りで、「純真」という花言葉があります。
Lowland populations of Bogbean are considered “glacial relicts.” Their wetland blooms are a crystalline white, beautifully fringed with delicate, thread-like filaments. In the language of flowers, they symbolize “innocence.”
【仮名】ミツガシワ
【和名】三槲
【英名】Bogbean, Buckbean
【学名】Menyanthes trifoliata
【誕生】03/ 29, 04/ 17, 05/ 19
【開花】04, 05, 06, 07月
【花色】White
ミツガシワ
ミツガシワの概要
ミツガシワはミツガシワ科の多年生抽水植物。氷河期には北半球に広く分布していましたが、後氷期に多くが北方や高山帯へ退きました。現在、低地に点在する自生群は「氷河遺存植物」。湿原に咲く花は透き通るような白色、糸状突起の縁飾りで、「純真」という花言葉があります。
ミツガシワの名前
ミツガシワの和名の由来は葉の形と着き方が柏の葉を組み合わせた家紋「三つ柏」に似るからです。英名ボグビーンは「湿地の豆」という意味で、葉が空豆に似ているから。属名メニアンテスは「花が長く咲き続ける」、種小名トリフォリアータは「三つの葉がある」という意味です。
ミツガシワの姿形
ミツガシワは根茎が泥中を這い、節々から髭根を伸ばします。葉は根生で柄が長く、３出複葉。小葉は倒卵形で表面に光沢があり、縁に緩い鋸歯があります。花は５裂で、縮れた毛が密生。茎先で穂状に咲き上がります。蒴果は熟すと裂けて種子を散布。種子は水に浮いて運ばれます。
ミツガシワの利用
ミツガシワは古くからの薬草。乾燥させた葉が生薬「睡菜葉」として文字通り鎮静や安眠のほか、苦味配糖体ロガニンが消化液の分泌を促し、健胃に用いられました。英国や北欧の一部では18世紀頃までビール作りに利用。苦味がホップの２～３倍あり、強烈な味わいだったようです。
Bogbean
Bogbean is a perennial aquatic plant belonging to the Menyanthaceae family. While it was widely distributed across the Northern Hemisphere during the Ice Age, most populations retreated to northern latitudes or alpine zones following the glacial period. Today, the scattered populations found in lowlands are precious “glacial relicts.” The flowers that grace the wetlands are a translucent white, characterized by their unique fringed petals, and carry the floral meaning of “innocence.”
The Japanese name for Bogbean, Mitsugashiwa, translates to “three oak leaves.” This is because the shape and arrangement of its leaves resemble a traditional Japanese family crest (kamon) that features three oak leaves. The English name “Bogbean” (also known as Buckbean) stems from the leaves’ resemblance to broad beans. Its genus name, Menyanthes, signifies “long-blooming,” while the species name, trifoliata, refers to its “three leaves.”
Bogbean features a creeping rhizome that spreads through the mud, extending fibrous roots from its nodes. The long-stemmed leaves are trifoliate (composed of three leaflets). Each leaflet is obovate (egg-shaped) with a glossy surface and slightly serrated edges. The five-lobed flowers are distinctive for their dense covering of white, curly hairs and bloom in upright spikes at the tips of the stems. When ripe, the capsules split open to scatter their seeds, which are then dispersed by floating on the water.
Bogbean has a long history as a medicinal herb. Its dried leaves were traditionally used as a herbal remedy for sedation and to promote sleep. Furthermore, it contains the bitter glycoside loganin, which was used as a digestive tonic to stimulate gastric secretions. In parts of Great Britain and Scandinavia, Bogbean was even used in brewing beer until around the 18th century. With a bitterness two to three times that of hops, it reportedly imparted a very intense flavor.
