Neotropical Rhizophoraceae

Description

Trees or shrubs. Leaves simple, opposite or verticillate, petiolate, margins entire or serrate, glabrous or with unicellular, simple hairs; stipule small to large, interpetiolar, caducous or subpersistent. Inflorescence of dichotomous axillary cymes, racemes or fasciculate or flowers solitary. Flowers hermaphrodite, actinomorphic; sepals 4-7, valvate; petals 4-7 free, equal in number and alternate to sepals, valvate, often unguiculate, margins often fimbriate or laciniate; stamens 8-40, inserted on margin of a lobed perigynous disc; anthers introrse, longitudinally dehiscent, dorsifiexed; ovary superior or inferior, 2-4-locular with 2 anatropous ovules in each loculus; ovules anatropous, pendulous, placentation axial; style filiform, erect, stigma 2-4-lobed. Fruit a capsule or a coriaceous, viviparous drupe, endosperm present.

Notes on delimitation

• Previously usually associated with the Myrtales or with the Celastraceae and Elaeocarpaceae.
• The Angiosperm Phylogeny Group clearly places this family in the Malpighiales near to the Erythroxylaceae.

Distribution in the Neotropics

• A pantropical family of 16 genera and about 120 species.
• Three genera occur in the Neotropics.

Distinguishing characters (always present)

• Opposite toothed leaves in some species.
• The viviparous drupe of Rhizophora L.
• The fimbriate or laciniate petals of Cassipourea Aubl. and Sterigmapetalum Kuhlm.
• Collecting veins occur in the leaves of some Cassipourea species.

Number of genera

Three:

• Rhizophora
• Cassipourea
• Sterigmapetalum

Useful tips for generic identification

Key to genera of Neotropical Rhizophoraceae

1. Ovary inferior; fruit a viviparous drupe; plants with stilt roots... Rhizophora
1. Ovary superior; fruit a capsule, plants without stilt roots... 2

2. Flowers hermaphrodite; leaves opposite; petals fimbriate or laciniate; inflorescence of solitary flowers or sessile clusters ... Cassipourea
2. Flowers dioecious; leaves verticellate; petals laciniate; inflorescence a corymobose panicle with long peduncle... Sterigmapetalum

Status

• Native to the Neotropics, but Rhizophora and Cassipourea also occur in the Old World.

General notes

• The genera Anisophyllea R.Br. ex Sabine and Polygonanthus Ducke have often been placed in this family, but they are now considered to be in a separate family, the Anisophylleaceae, which belongs in the Cucurbitales.

Important literature

Prance, G.T. and Silva, M.F. 1975. Revisão taxonômica das espécies amazônicas de Rhizophoraceae. Acta Amazonica 5 (1): 5-22.

Prance, G.T.  2001. Rhizophoraceae. Flora of Nicaragua. Monographs in Systematic Botany 85, 3: 2200-2201.

How to cite

Prance, G.T. (2009). Neotropical Rhizophoraceae. 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/Rhizophoraceae.htm.