Ochnaceae

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Ochnaceae

Description

Woody plants, very small undershrubs to tall trees. Leaves distichous or spirally arranged, stipulate, simple, glabrous; Inflorescences 1- to many-flowered, cymose, racemose, or thyrsoid, bracteate; Flowers actinomorphic, bisexual (rarely functionally polygamous). Sepals 5, free or a little connate at base, quincuncial, persistent. Petals 5-10, free, contort, caducous. Stamens 5-10-∞; Fruit(s) a drupe(s), berry, or capsule. Seeds 1-∞, small or large, sometimes winged, with or without albumen.

Distribution

Africa: present Asia-Tropical:, Jawa (Jawapresent); Lesser Sunda Is.present Continental SE. Asia: present N. India: present S. Africa: present S. America: present Southern America:, Brazil North (Roraimapresent) W. Malesia: present northern S. America: present tropical, rarely subtropical countries: present western part of Malesia: present
About 30 genera and c. 250 spp. through the tropical, rarely subtropical countries (S. Africa, N. India), chiefly in S. America and Africa. In Malesia 8 genera and 13 spp.; absent from Java and the Lesser Sunda Islands.
In subfam. Ochnoideae, the monogeneric tribe Elvasieae and the genus Ouratea are restricted to S. America. Of the 3 genera of the Ochneae mentioned above, only Brackenridgea is chiefly Malesian. Ochna and Gomphia are principally African, both reaching the western part of Malesia with one species.
In subfam. Sauvagesioideae, the monogeneric tribe Lophireae occurs only in Africa, whereas the sub-tribe Luxemburgiinae is restricted to S. America. The 5 relevant genera mentioned above are almost purely Malesian. Of the subtribe Sauvagesiinae, Sinia DIELS and Indosinia VIDAL are found in continental SE. Asia, whereas the majority of the genera is restricted to S. America, only Sauvagesia L. occurring both in S. America and Africa.
There is an interesting parallelism between some of the Sauvagesioideae, which are more or less restricted to sandstone areas in W. Malesia, and related genera found in similar areas in northern S. America (Roraima flora).

Pollination

There is no literature on this subject. Pollination probably takes place by insects, because of the brightly coloured and (sometimes?) scented flowers. The colours of the petals are yellow in Ochna and Brackenridgea sect. Notochnella, mostly white, creamy, or tinged purple in other genera, sometimes dark purplish red in Schuurmansia. Only Ochna has flowers c. 3 cm across. Flowers of other genera usually do not exceed 1 cm, but they are often combined to conspicuous inflorescences. The undershrubs of Neckia, however, have solitary flowers with relatively small, early caducous petals.

Dispersal

The bluish or black, 1-seeded fruits of the Malesian Ochneae are probably mainly dispersed by birds. In Ochna and Brackenridgea they are contrasting with a purple calyx and torus. The Euthemideae have red or white berries on a dark red calyx, which are probably also dispersed by birds (see ). The Malesian Sauvagesieae have many-seeded capsules. Their seeds do not show adaptations to a special mode of dispersal, except those of Schuurmansia with two wings like propeller blades. The latter characteristic points to wind dispersal, which fits the pioneer-like nature of the genus concerned. The sepals in Neckia are also turning dark purple in fruit; the meaning of this phenomenon is not understood.

Morphology

From the description of the family and the key to the genera it will be clear that the morphological differences between subfamilies and tribes are considerable. A discussion on these differences I gave in my thesis (). A short note should be made here on the inflorescence types, as these may not always be easily understood.
The inflorescences in subfam. Ochnoideae are all considered to be of a thyrsoid nature, viz racemes with cymose branches. Those of Gomphia serrata are lateral and terminal, bearing terminal flowers which makes sympodial growth of the vegetative branches necessary. Those of Ochna integerrima have also terminal flowers, but they are terminal on short side branches and monopodial growth of the main branches remains possible. The inflorescences of Brackenridgea spp. are terminal, sometimes also lateral. A terminal flower is lacking and monopodial growth of the rachis to a vegetative shoot is still possible, although not equally frequent in all species. The cymose branches are very much shortened here, especially in sect. Brackenridgea where flowers are almost sessile on the rachis. In some species there are several branches per inflorescence, each bearing 3(-5) flowers. In other species there are only a few branches, each bearing 7 or more flowers in pseudo-umbels. In sect. Notochnella the cymose branches are not shortened so much, whereas the bracts on the rachis sometimes have a more leaf-like appearance. The inflorescences in subfam. Sauvagesioideae are more of a paniculate nature. They are profusely branching in Schuurmansia, but in the other genera most branches are very much shortened, flowers and fruits of different age standing closely together. In Neckia the rachis is bearing several bracts, but only one (terminal?) flower.

Anatomy

The Ochnaceae are characterised by the presence of cortical bundles without resin canals (). The subfam. Ochnoideae shows typical ‘cristarque’ cells in branches and leaves (). For other data, see , and .

Taxonomy

There is little doubt that the family of the Ochnaceae represents a natural one among the more primitive in the Guttiferales (= Clusiales or Theales s. l.). Nonetheless, there are striking differences between the genera, even at first sight. It is not difficult to arrange them in a few distinct, supra-generic taxa. A supposed natural system, as far as relevant to the Malesian genera, is as follows:
  • Subfamily Ochnoideae
    • Tribe OCHNEAE.
      • Subtribe Ochninae
        • 1.Ochna
        • 2. Brackenridgea
      • Subtribe Ouratinae
        • 3. Gomphia
  • Subfamily Sauvagesioideae
    • Tribe EUTHEMIDEAE.
        • 4.Euthemis
    • Tribe SAUVAGESIEAE.
      • Subtribe Sauvagesiinae
        • 5.Neckia
        • 6.Indovethia
        • 7.Schuurmansiella
        • 8. Schuurmansia

Uses

No economically important applications of Malesian spp. have been recorded. For properties of the wood of some species, see under Ochna integerrima and Gomphia serrata.

Notes

The present revision is based on my precursory treatment of Indo-Pacific Ochnaceae in .

Phytochemo

No data available. Some species are used locally for medicinal purposes, because of bitter components of unknown nature.