Neotropical Actinidiaceae

Description

Shrubs to treelets, rarely trees, often climbing, with twining stems; plants monoecious or dioecious. Leaves simple, alternate, estipulate, entire, margins always serrate to crenate, hispid hairs almost always present, especially on stems, inflorescences and petioles. Inflorescence racemose or paniculate, bracteate. Flowers showy, hermaphrodite (unisexual in Actinidia), actinomorphic, bracteolate, often drooping or facing downards; sepals usually (3-)5(-8), free; petals (3-)4-5(-8), white or cream-coloured, rarely pink; stamens many (more than 30), fused to inside of petals, anthers 2-locular; ovary superior, (3-) 5 (-7)-carpelate, multi-ovulate, placentation axile, ovary crowned by several stigmas.  Fruit a succulent, indehiscent berry, sometimes covered in stiff hairs; seeds very numerous, small, black, tear-shaped.

Notes on delimitation

• The Actinidiaceae fits within order Ericales, together with the Ericaceae and Clethraceae (APG II, 2003, Souza & Lorenzi 2005).

Distribution in the Neotropics

• In the Neotropics, the Actinidiaceae is represented by the native genus Saurauia (absent from Brasil) and by the cultivated Actinidia chinensis Planch., the kiwi fruit.

Distinguishing characters (always present)

• Leaves with many pairs of veins, margins serrate.
• Flowers drooping, with indefinite number of stamens, showy, clustered in dense inflorescences.
• Ovary with many locules and multi-ovulate, crowned by several stigmas.
• Berry with many small seeds and fleshy pulp.
  

Other important characters

• Leaves alternate, simple, sometimes clustered together, almost always with long, hispid hairs.
• Berry sometimes hairy.

Key differences from similar families

• Resembles Clethraceae but flowers are more showy and fruit a berry.

Number of genera

• 1. Saurauia Willd. - 280 species worldwide, of which nearly 50 occur in the Neotropics.
• 2. Actinidia L. - Actinidia deliciosa (A. Chev.) Liang & A.R. Ferg. is often cultivated for its edible fruit, the kiwi.

Status

• Saurauia occurs from Central Mexico to Bolivia but  is absent from Brazil, Argentina, Paraguay, Uruguay and Chile.

Important literature

APG II, 2003. An update of the Angiosperm Phylogeny group classification for the orders and families of flowering plants: APG II. Bot. J. Linn. Soc. 141(4): 399-436.

Soejarto, D.D. 1980. Revision of South American Saurauia (Actinidiaceae). Fieldiana (Botany), new series 2: 1-141.

Souza, V.C. & Lorenzi, H. 2005. Botânica Sistemática: guia ilustrativo para identificação das famílias de Angiospermas da flora brasileira, baseado em APG II. Nova Odessa, Brazil: Instituto Plantarum.

How to cite

Zappi, D. (2009). Neotropical Actinidiaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Actinidiaceae.htm.