''Arisaema thunbergii'' subsp. ''urashima'' is a herbaceous

perennial plant A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

. It is widespread through the woodlands of Japan, especially near the coast. The plant has a very curious

inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

, and is popular in horticulture. As with all arisaemas, the inflorescence consists of a

spathe In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

tube enclosing a spadix appendix. In the case of ''A. thunbergi'' subsp. ''urashima'', the spadix appendix is elongated into a free hanging thread of 45 to 60 cm. The underground

tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growin ...

often produces offsets, which can be removed and grown on. The foliage dies down by summer, leaving the fruiting spike to ripen in autumn. The red berries contain high amounts of oxalic acid, and can cause painful irritation to the skin. All parts of the plant should be considered poisonous.

References

Arisaema thunbergii or Arisaema urashima in Mount Ryozen 2011-06-04

thunbergii subsp. urashima Plant subspecies Endemic flora of Japan {{Araceae-stub