Hedera rhombea, the Japanese ivy or songak, is a species of ivy[2] in the Araliaceae family native to East Asia. It is native to Japan, the Korean Peninsula, the Ryukyu Islands, and Taiwan,[1] where it is common on rocky slopes and growing up the trunks of trees, especially in laurel forest, a type of cloud forest.

Hedera rhombea
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Apiales
Family: Araliaceae
Genus: Hedera
Species:
H. rhombea
Binomial name
Hedera rhombea
(Miq.) Paul (1867)
Varieties[1]
  • Hedera rhombea var. formosana (Nakai) H.L.Li
  • Hedera rhombea var. rhombea
Synonyms

Hedera helix var. rhombea Miq. (1863)

Description

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It is an evergreen climbing plant, growing to 10 m high where suitable surfaces (trees, cliffs, walls) are available, and also growing as ground cover where there are no vertical surfaces. It climbs by means of aerial rootlets which cling to the substrate. Stems are green, poisonous if eaten and have an irritating sap. It is cultivated in gardens and used in floral arrangements.[2]

The leaves are medium green and have a rhombic diamond shape that give it its species name, rhombea. Leaves have a glossy, dark green petiole. The bisexual flowers are 4–5 mm in diameter and yellow-green, in erect umbels. The round fruits are black when ripe.[2]

Varieties

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Two subspecies are accepted.[1]

  • Hedera rhombea var. formosana (Nakai) H.L.Li (synonym Hedera formosana Nakai) – Taiwan[3]
  • Hedera rhombea var. rhombea (synonyms Hedera japonica Tobler, H. japonica Paul, H. pedunculata Nakai, H. rhomboidea G.W.Johnson, H. submarginata (Hibberd) Carrière, and H. tobleri Nakai) – Japan, Korea, and the Ryukyu Islands[4]

References

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  1. ^ a b c "Hedera rhombea (Miq.) Paul". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 11 October 2024.
  2. ^ a b c "Hedera rhombea (Japanese Ivy)". North Carolina Extension Gardener Plant Toolbox. North Carolina Cooperative Extension. Retrieved 11 October 2024.
  3. ^ "Hedera rhombea var. formosana (Nakai) H.L.Li". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 11 October 2024.
  4. ^ "Hedera rhombea var. rhombea". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 11 October 2024.