Dendrobium

A general term for the genus Dendrobium in the family Orchidaceae (APG classification: Orchidaceae). The second largest genus of orchid plants. Approximately 1,000 species are distributed mainly in tropical Asia and New Guinea, and two species, including Dendrobium moniliforme (L.) Sw., grow wild in Japan. Many species grow high on trees and produce beautiful flowers. There are two groups of species that are widely cultivated for horticulture: the Nobile group and the Dendrobium phalaenopsis group.

The Nobile species is a strain that has been improved mainly from Dendrobium nobile Lindl., which is found from northern India to southern China. The stems are thick and grow to 30-70 cm. In autumn of the following year, two or three flowers appear at each node of the shed stem, and they bloom from winter to spring. They are used as potted plants and cut flowers. Hybrid varieties with Dendrobium bigibbum are small and strong. The Dendrobium phalaenopsis species is a strain that has been improved mainly from Dendrobium bigibbum Lindl. ( D. phalaenopsis Fitzg.), which is found near the island of New Guinea. They grow long flower stalks from the top of stems about one meter long, and produce more than ten flowers, making them suitable for cut flowers. Most flowers bloom in autumn, but there are also varieties that bloom all year round.

They are generally planted in small terracotta pots made of sphagnum moss, watered thoroughly during the growing season, and kept on the dry side from autumn to spring. Do not fertilize after summer, and expose to plenty of sunlight just enough to avoid leaf burn. Flower buds are produced by low temperatures, so they will not flower unless they are exposed to sufficient cold in late autumn (10°C, for at least two weeks) before being brought indoors. Nobile species will overwinter at a minimum of 10°C, and hybrids with Dendrobium frutescens will overwinter at 5-6°C. Dendrobium phalaenopsis species thrive in high temperatures, and should be cultivated at a minimum of 17°C in winter.

[Koji Karasawa May 21, 2019]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

ラン科（APG分類：ラン科）セッコク属の総称。ラン科植物中2番目の大属。約1000種が熱帯アジア、ニューギニア島を中心に分布し、日本にもセッコクD. moniliforme (L.) Sw.ほか2種が自生する。樹上高く着生し、美しい花をつける種が多い。園芸的に広く栽培されるものにはノビル系とデンファレ系の二つのグループがある。

　ノビル系はインド北部から中国南部にかけて産するデンドロビウム・ノビルD. nobile Lindl.を中心に改良された系統で、茎が肥厚し、30～70センチメートルに伸び、次の年の秋、落葉した茎の各節に2、3個ずつ花をつけ、冬から春に開花する。鉢物、切り花として利用される。セッコクとの交雑品種は小形で強健である。デンファレ系はニューギニア島近辺に産するデンドロビウム・ファレノプシスD. bigibbum Lindl.（D. phalaenopsis Fitzg.）を中心に改良された系統で、1メートル前後の茎の上部から、長い花茎を伸ばして10花余りをつけ、切り花に適する。花は秋に多く咲くが、周年開花する品種もある。

　一般にミズゴケで小さめの素焼鉢に植え、生育期には十分灌水(かんすい)し、秋から春までは乾きめに扱う。夏以降は肥料を与えず、葉焼けしない程度によく日光に当てる。花芽は低温によってつくられるので、晩秋十分な寒さ（10℃、2週間以上）に当ててから室内に取り込まないと花がつかない。ノビル系は最低10℃で越冬する。またセッコクとの交雑種は5～6℃で越冬する。デンファレ系は高温で育ち、冬期は最低17℃で栽培する。

［唐澤耕司　2019年5月21日］

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