Juncaceae - Juncaceae

A monocotyledonous plant. Perennial, rarely annual or shrub. Leaves alternate, growing at the base of the stem or clustered at the bottom. Flowers are small, bisexual, rarely unisexual, dioecious, and actinosymmetric. Dry, scale-like tepals, three on the inside and three on the outside, rarely two each, sometimes with a single inner tepal that is not developed. Stamens are three or six, rarely two. Pistils are three-carpellic, ovary is superior, three-lobed or one-lobed, capsules are formed on the back of the locust that split. Flowers lack nectar glands, and are wind-pollinated. Based on the nature of the tepals and chemical composition, it is thought to be closely related to the Poaceae (APG classification: Poaceae) and Cyperaceae (APG classification: Cyperaceae).

There are about 300 species in two genera in the temperate and cold zones of the Northern Hemisphere, and about 10 species in six genera in the Southern Hemisphere. In Japan, there are about 30 species in two genera, the genera Juncus and Pycnonotida, that grow naturally.

[Takemi Shimizu July 19, 2019]

It is also classified as Juncaceae in the APG classification.

[Editorial Department, July 19, 2019]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

単子葉植物。多年草、ごくまれに一年草または低木。葉は互生し、根際につくか茎の下部に集まる。花は小形、両性まれに単性で雌雄異株につき放射相称。花被片(かひへん)は乾質の鱗片(りんぺん)状、内外それぞれ3枚、まれに2枚ずつ、ときに内花被が発達せず1輪となる。雄しべは3または6本、まれに2本。雌しべは3心皮性、子房は上位で3室または1室、室の背面で裂ける蒴果(さくか)を結ぶ。花には蜜腺(みつせん)がなく、風媒花。花被片の性質や化学成分などから、イネ科（APG分類：イネ科）やカヤツリグサ科（APG分類：カヤツリグサ科）に近縁と考えられている。

　北半球の温帯から寒帯に2属約300種、南半球に6属10種ほどがある。日本にはイグサ属とスズメノヤリ属の2属三十数種が自生する。

［清水建美　2019年7月19日］

　APG分類でもイグサ科とされる。

［編集部　2019年7月19日］

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