Asaza - Floating heart

A perennial aquatic plant of the Menyanthaceae family (APG classification: Menyanthaceae). The leaves are ovate or broadly elliptical, with wavy sawtooth edges, and the petioles are slightly shield-shaped. From June to August, the flower stalks grow above the water surface, and bright yellow flowers bloom during the day. The corolla is deeply divided into five lobes, with long hairs on the edges of the lobes. The seeds are flattened, with thick wings and long protuberances on the edges. The name is said to be a derivative of "asa asa" (shallow water greens) because it grows in shallow water. It is also known as Hana Junsai. It grows in ponds and marshes in Honshu, Shikoku, Kyushu, and Okinawa west of Miyagi Prefecture, and is also widely distributed from the Korean Peninsula and China to the subtropics and tropics of the Eurasian continent. In addition, the flowers of the Flounder genus grow in clusters at the nodes, and many of the petals have hairs. There are approximately 50 species distributed worldwide, with three species in Japan.

[Hideo Takahashi November 17, 2021]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

ミツガシワ科（APG分類：ミツガシワ科）の多年生の水草。葉は卵形または広楕円(こうだえん)形で、縁辺は波状の鋸歯(きょし)があり、葉柄はわずかに楯(たて)状につく。6～8月、水面より高く花柄を伸ばし、鮮黄色の花を日中開く。花冠は深く5裂し、裂片の縁に長毛がある。種子は扁平(へんぺい)で厚い翼ができ、縁辺に長い突起がある。名は、水の浅い所に生え、「浅浅菜」の転じたものといわれる。ハナジュンサイの名もある。宮城県以西の本州、四国、九州、沖縄の池や沼に生え、さらに、朝鮮半島、中国からユーラシア大陸の亜熱帯から熱帯に広く分布する。なおアサザ属は、花は節に束生し、多くは花弁に毛がある。世界に約50種、日本に3種が分布する。

［高橋秀男　2021年11月17日］

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