Cactus (plural: cacti) was a name originally used for a spiny plant whose identity is not certain. Cacti are native to the Americas.
Most cacti live in habitats subject to at least some drought. Many live in extremely dry environments. Cacti show many adaptations to conserve water. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. Cactus spines are produced from specialized structures called areoles, a kind of highly reduced branch. Areoles are an identifying feature of cacti. As well as spines, areoles give rise to flowers, which are usually tubular and multi-petaled.
COPYRIGHT NOTICE
ALL IMAGES CONTAINED IN THIS WEB SITE REMAIN THE PROPERTY OF RON LEGGAT. IMAGES MAY NOT BE DOWNLOADED, REPRODUCED, COPIED OR USED IN ANY OTHER WAY WITHOUT EXPRESS WRITTEN PERMISSION.
Ref: DSC_0197_pe0014_lo
Date: 10/07/2012
Location: Madeira, Portugal
Photographer: Ron Leggat ARPS