Ivy - Taxonomy

Taxonomy

The following species are widely accepted; they are divided into two main groups, depending on whether they have scale-like or stellate trichomes on the undersides of the leaves:

  • Trichomes scale-like
    • Hedera algeriensis Hibberd – Algerian ivy. Algeria, Tunisia (Mediterranean coast).
    • Hedera canariensis Willd. – Canaries ivy. Canary Islands.
    • Hedera colchica (K.Koch) K.Koch – Persian ivy. Alborz, Caucasus, Turkey.
    • Hedera cypria McAllister – Cyprus ivy (syn. H. pastuchovii subsp. cypria (McAll.) Hand). Cyprus (Troodos Mts.)
    • Hedera iberica (McAllister) Ackerfield & J.Wen – Iberian ivy. SW Iberian coasts.
    • Hedera maderensis – Madeiran ivy. Madeira.
    • Hedera maroccana McAllister – Moroccan ivy. Morocco.
    • Hedera nepalensis K.Koch – Himalayan ivy (syn. H. sinensis (Tobl.) Hand.-Mazz.). Himalaya, SW China.
    • Hedera pastuchowii G.Woronow – Pastuchov's ivy. Caucasus, Alborz.
    • Hedera rhombea (Miq.) Siebold ex Bean – Japanese ivy. Japan, Korea, Taiwan.
  • Trichomes stellate
    • Hedera azorica Carrière – Azores ivy. Azores.
    • Hedera helix L. – Common ivy (syn. H. caucasigena Pojark., H. taurica (Hibberd) Carrière). Europe, widespread.
    • Hedera hibernica (G.Kirchn.) Bean – Atlantic ivy (syn. H. helix subsp. hibernica (G.Kirchn.) D.C.McClint.). Atlantic western Europe.

The species of ivy are largely allopatric and closely related, and many have on occasion been treated as varieties or subspecies of H. helix, the first species described. Several additional species have been described in the southern parts of the former Soviet Union, but are not regarded as distinct by most botanists.

The only verified hybrid involving ivies is the intergeneric hybrid × Fatshedera lizei, a cross between Fatsia japonica and Hedera hibernica. This hybrid was produced once in a garden in France in 1910 and never successfully repeated, the hybrid being maintained in cultivation by vegetative propagation. Despite the close relationship between Hedera helix and H. hibernica (until relatively recently considered conspecific), no hybrids between them have yet been found. Hybridisation may however have played a part in the evolution of some species in the genus.

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