Ishimikawa - Ishimikawa

An annual plant of the Polygonaceae family (APG classification: Polygonaceae). The stem grows to over 2 meters, is glabrous throughout the plant, has inverted thorns, and wraps around other plants. The leaves are alternate, triangular, bluntly pointed, thin, greenish-white, 3-6 cm long, and have long petioles with inverted thorns attached to the blade in a shield-like shape. The stipules are also shield-shaped. Flowers appear from August to October in short spikes, with 1.5 mm pedicels, greenish-white perianths 3 mm long with 5 lobes, and broad elliptical lobes. The achene is indigo blue, spherical, and 3 mm in diameter. It grows in fields, roadsides, and other grasslands throughout Japan, and is widely distributed in China, Malaysia, India, and other places. The origin of the name is unclear, but it is said to be a stone seed coat because of the hard seed coat.

[Junko Kobayashi December 11, 2020]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

タデ科（APG分類：タデ科）の一年草。茎は2メートル余に伸び、全草無毛で逆向きの刺(とげ)があり、他物に巻き付く。葉は互生し、三角形で先が鈍くとがり、薄質で緑白色、長さ3～6センチメートル、葉柄は長く逆向きの刺があり葉身に楯(たて)状につく。托葉(たくよう)も楯形。花は8～10月、短い穂状花序につき、小花柄は1.5ミリメートル、花被(かひ)は緑白色、長さ3ミリメートルで5中裂し、裂片は広楕円(こうだえん)形。痩果(そうか)は藍(あい)色、球形で径3ミリメートル。日本全土の畑や道端などの草地に生え、中国、マレーシア、インドなどに広く分布する。名の由来はよくわからないが、種皮が堅いことから石実皮であろうといわれる。

［小林純子　2020年12月11日］

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