noun, plural: cacti
A cactus is an angiosperm in the family Cactaceae. This family is comprised of thousands of species characterized by having thick, fleshy stems. Members of this family also usually have showy flowers. They are found thriving in hot, driest places and semi-desert habitats. They are able to survive in these places due to their morphological and physiological adaptations in conserving water. Most cacti have succulent plant parts, particularly their stem. Within these plant parts is water that is conserved. Most of them also do not have true leaves. What they have though are modified leaves that appear as spines on their stem. This feature helps cacti against water loss and herbivory. Since they have no true leaves, cacti usually have green stems. Photosynthesis occurs mostly in their stems.
The family Cactaceae includes the following subfamilies: Cactoideae, Maihuenioideae, Opuntioideae, and Pereskioideae.
Word origin: Latin cactus, Ancient Greek káktos (“cardoon”)