Melocactus conoideus is a critically endangered cactus from eastern Brazil.
Melocactus conoideus in the wild in the Serra do Periperi, near Vitoria da Conquista, Bahia, Eastern Brazil (Photo: Marlon Machado)
Melocactus conoideus Buining & Brederoo
Rated by IUCN as Critically Endangered.
At times a fire-swept cerrado/campo rupestre/caatinga transition area, but in appearance most like the campo rupestre phase known as campo sujo, with sparse low shrubs and herbs but no trees; under and between shrubs in quartz gravel. More details below.
This cactus bears short spines.
About this species
The strongly depressed (squat) habit of this species is thought to be an adaptation to minimise the effects of fire, although it can still get scorched on occasion.
It grows with another more common Melocactus, M. concinnus, which is typical of the campo rupestre / caatinga ecotone (transition area between different plant communities). Both are beautiful and popular plants in cultivation in Europe and elsewhere amongst cactus hobbyists. Their mass propagation, in places like the Canary Islands, has helped reduce the desire for wild-collection and export, which is banned under international law (CITES). However, some stock produced ex situ in this way may be impure due to hybridization in nursery stands.
The curious bristly head of the plant, known as a 'cephalium', is typical of this genus (Melocactus) and represents a specialised structure in which the flowers and fruits are borne and protected.
Geography and distribution
Restricted to the state of Bahia in eastern Brazil. Found in Serra do Periperi, Vitoria da Conquista, in south-eastern Bahia, at 900-1,050 m above sea level. Melocactus conoideus grows in the transition area between the following habitats:
- Cerrado/ Savanna – a low, open, seasonal, semi-evergreen woodland or parkland-like area on nutrient-deficient, acid soils. This area is often subject to fire during the dry (winter) season.
- Campo rupestre – rocky upland habitat, with diverse geology, drainage and atmospheric humidity. This area is often described as a complex mosaic of micro-habitats.
- Caatinga – seasonally very hot and dry thorn forest, where the majority of plants lose their leaves during the dry (winter) season.
The stem of this cactus is shaped like a sphere that has been squashed from above, or tending to hemispherical, and is 10-17 cm in diameter. The stem has 11 to 15 ribs, which are very low and rounded, and are up to 2.5 x 4 cm. The areoles (small, cushion-like areas from which the spines arise) are 6.5-7.5 x 6.5 mm. The spines are dark brown overlaid with grey. Each areole has one central spine of 20-22 x 1.5 mm and 8-11 radial spines, which are straight to slightly curved at the tips.
The pinkish-magenta flowers are about 22 x 10 mm, and the lilac-magenta fruits are 18-21 x 5-6 mm, both borne in the fairly short, reddish-bristly cephalium, which caps the vegetative part of the stem.
Seeds are 1.05 -1.25 x 0.9-1.05 mm, testa-cells strongly convex at periphery.
Threats and conservation
The extent of occurrence of Melocactus conoideus is less than 100 km² and the area of occupancy is estimated to be less than 10 km². Its survival in the wild continues to be severely threatened by extraction of the quartz gravel in which it grows. It has also been affected by commercial collection for the European horticultural market. It has been listed on CITES Appendix I since June 1992.
M. conoideus appeared to be close to extinction in the Serra do Periperi above Vitoria da Conquista in 1989, but healthy extensions of the population exist in similar habitat in adjacent areas (some of these including thousands of individuals).
Kew scientist Nigel Taylor helped evaluate a bid to the British Cactus & Succulent Society's Conservation Committee, which resulted in a grant to fence the reserve area created by the municipality of Vitoria da Conquista. This reserve area is maintained by local enthusiasts, who have since successfully planted seedlings to reinforce the population.
Melocactus conoideus is cultivated as an ornamental, particularly in Europe.
Where to see this at Kew
Melocactus conoideus is grown in the Tropical Nursery, one of the behind-the-scenes areas of Kew.
Dried and alcohol-preserved specimens are held in the Herbarium, where they are made available to bona fide researchers by appointment. Details of some of these specimens can be seen in the online Herbarium Catalogue.
Taylor, N.P. & Zappi, D. (2004). Cacti of Eastern Brazil. Royal Botanic Gardens, Kew, London.
Kew Science Editor: Nigel Taylor
Kew contributors: Daniela Zappi
Copyediting: Emma Tredwell
Kew would like to thank the following contributors: Marlon Machado
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