Common name: Royal tree

Guapeba or Royal tree is an endangered timber and fruit-bearing tree originating in Brazil, its natural range limited to small areas of subtropical forest in the south-east of the country, in the vicinity of San Paulo and Rio de Janeiro.

It may reach heights of up to 25 m (80 ft) in its natural habitat, though is more typically 12 to 20 m (40 to 65 ft) tall and develops a straight trunk with fissured, light brown bark and a rounded crown of large showy evergreen leaves.

The leaves are club-shaped, very large, up to 40 cm (1.3 ft) long, dark glossy green and prominently ribbed on top, dull green underneath, toothed on the margins and in a spiral arrangement at the ends of the branches. The young leaves emerge cream-brown, contrasting strongly against the green of the older leaves.

In late spring to summer, small creamy-white flowers bloom in loose clusters at the ends of the branches, though are mostly hidden by the leaves. They are followed by small, round, green fruit that turn pale yellow when ripe, usually from late autumn to winter. 

Use

It is listed as an endangered species by the International Union for Conservation of Nature (IUCN), which brings attention to its conservation needs. Because of its rarity, it is seldom found in the wild and nowadays is mostly encountered growing on the grounds of botanical or other public gardens.

The wood is reported to be heavy and hard and was used extensively in shipbuilding before the urbanisation of its natural habitat put the tree under the threat of extinction.

The fruit is esteemed in its native area for its creamy, translucent, sweet-tasting pulp, which is somewhat similar to that of the closely related Star Apple (Chrysophyllum cainito).

Climate

Grows naturally in lowland to mid-elevation forest environments up to 800 meters elevation in south-eastern Brazil. The climate in its natural habitat is moderately humid subtropical to tropical, generally frost-free areas with annual lows of 12 to 20°C annual highs of 22 to 29°C, annual rainfall of 1000 to 2500 mm and a dry season of 4 months or less.

Growing

New plants are usually grown from seed, but they have a low germination rate. It performs best on moist, free-draining clay and loam soils of a moderately acid to neutral nature, generally with a pH of 5.0 to 7.5 and on sites with full to partial sun exposure. It has good tolerance to seasonal flooding.

Problem features

There does not appear to be any records of it as a weed and because of its poor seed germination rate is unlikely to establish as a weed outside of cultivation.

Books

• Barwick, M., et al. 2004, Tropical & subtropical trees : a worldwide encyclopaedic guide, Thames and Hudson, London

• Davis, S.D., et al. 1997, Centres of Plant Diversity: A Guide and Strategy for Their Conservation (3 volumes), IUCN Publications Unit, Cambridge, Cambridgeshire

• Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia