Saurocory in Melocactus violaceus (Cactaceae)
1994; Wiley; Volume: 26; Issue: 3 Linguagem: Inglês
10.2307/2388850
ISSN1744-7429
AutoresJosé Eugênio Côrtes Figueira, João Vasconcellos‐Neto, Maria Alice Amorim Garcia, Andréa Lúcia Teixeira de Souza,
Tópico(s)Plant Diversity and Evolution
ResumoThe button cactus, Melocactus violaceus (Cactaceae), occurs in open, sandy soils in southern Brazilian coastal areas. The fruits of this species are pink, cone-shaped, and have a high water content and low sugar concentration. The fruits of M. violaceus develop while completely protected inside the cephalium and are driven out by internal pressure when ripe. Fruits can be exposed in only a few minutes during the hottest part of the day, and they become easily visible over the cephalium. They are expelled more quickly when temperature is high and lizards are more active. During the dry season these fruits appear to be eaten exclusively by the lizard Tropidurus torquatus (Tropiduridae). The cephalium is positioned close to soil level and the bright color of the fruits apparently improves fruit detection. Lizards defecate viable M. violaceus seeds. These seeds germinated quickly under laboratory conditions, while seeds collected directly from ripe fruits did not germinate under the same conditions. Cactus and fruit morphology, and the diurnal pattern of fruit release, may represent a suite of adaptations for dispersal by Tropidurus torquatus.
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