Iwarenge - Iwarenge

A monocarpic plant of the Crassulaceae family (APG classification: Crassulaceae). It is a perennial plant, but dies after flowering. When there were few foreign succulent ornamental plants, it was widely cultivated, and many horticultural varieties were developed, especially during the Meiji period. It is a species endemic to Japan, growing wild in the coastal areas of Honshu, west of the Kanto region, and Kyushu, on rocks and thatched roofs. The above-ground part is fleshy overall, powdery and whitish-green. It produces rosettes throughout the year, some of which are as large as 10 cm in diameter. The leaves of the rosettes are oblanceolate, 4 to 6 cm long, with rounded tips, and do not have needle-like protrusions like those of the Japanese jasmine. The inflorescence is dense and conical, and grows above the central axis of the elongated rosette. The flowers are pentamerous, and open from the bottom of the inflorescence in September to November. The petals are white, narrowly oblanceolate and about 7 mm long. The anthers are yellow before dehiscing. A variety called Komochirenge (Komochirenge) grows wild in Hokkaido, and its rosettes are small, measuring about 3 cm in diameter. Many produce runners from the sides of the rosette leaves. O. malacophylla (Pall.) Fisch. is widely distributed in East Asia, and in Japan it grows on rocks on the coasts and inland areas of Hokkaido, the Tohoku region, and northern Kyushu. It is similar to Iwarenge, but is not pollen-bearing and is green, and the anthers are deep reddish purple before dehiscing.

[Hideaki Ooba March 18, 2020]

The first illustration of this flower in Japan was in Nakamura Tekisai's Kinmo Zui (1666), and in the late Edo period, varieties with variegated leaves appeared. In the 1890s and 1900s, this flower enjoyed an extraordinary boom, with varieties such as Fuji, Houou, Kinboshi, Ryutou, and Kazan being traded speculatively. Also, in an era when 1 kilogram of rice cost 5 sen, one bud was traded for 10 to 20 yen, and famous varieties were sold for as much as 100 yen. Many varieties have since disappeared, but varieties such as Fuji with white leaves, Kinboshi with yellow leaves, and Houou with yellow leaves remain to this day.

[Hiroshi Yuasa March 18, 2020]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

ベンケイソウ科（APG分類：ベンケイソウ科）の一稔性(いちねんせい)植物。多年草だが、開花すれば枯死する。外国産の多肉観葉植物が少なかったころには、盛んに栽培され、とくに明治年間には多数の園芸品種が作出された。日本特産種で、関東地方以西の本州、九州の沿海地に野生し、岩上や藁葺(わらぶ)き屋根などに生える。地上部は全体に多肉で、帯粉して白緑色となる。通年にわたり、大きなものでは径10センチメートルになるロゼットをつくる。ロゼットの葉は倒披針(とうひしん)形で、長さ4～6センチメートルあり、先端は円く、ツメレンゲのような針状の突起はない。花序は密な円錐(えんすい)状で、伸長したロゼットの中央の軸の上方につく。花は5数性で、9～11月に花序の下方から開いてゆく。花弁は白色、狭倒披針形で長さ約7ミリメートル。裂開前の葯(やく)は黄色。変種のコモチレンゲ（子持蓮華）は北海道に自生し、ロゼットは径約3センチメートルと小さい。多くはロゼットの葉のわきから走出枝を出す。アオノイワレンゲO. malacophylla (Pall.) Fisch.は東アジアに広く分布し、日本では北海道、東北地方、九州北部の海岸や内陸部の岩上に生える。イワレンゲに似るが、帯粉せず緑色で、裂開前の葯は濃い赤紫色になる。

［大場秀章　2020年3月18日］

　日本で初めてこの花が図示されたのは、中村惕斎(てきさい)の『訓蒙図彙(きんもうずい)』（1666）で、江戸後期には覆輪(ふくりん)の斑入(ふい)り品が出現した。明治30～40年代には異常なブームをよび、富士、鳳凰(ほうおう)、金星、竜登(りゅうとう)、花山(かざん)などの品種が投機的に取引された。また、米1キログラムが5銭の時代に、1芽が10～20円で取引され、銘品は100円もの高値がついた。その後多くの品種は消失したが、葉が白覆輪の富士、黄覆輪の金星、黄中斑(きなかふ)の鳳凰などは現在も残る。

［湯浅浩史　2020年3月18日］

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