What is the tallest cactus species in the world?
Pachycereus pringlei is the tallest free-standing cactus, with a maximum recorded height of 19.2 m. The smallest, Blossfeldia liliputiana, reaches only about 1 cm in diameter at maturity.
Questions about Cactus
Short answers, pulled from the story.
How do cacti photosynthesize without leaves?
Cacti carry out photosynthesis in their stems, which contain chlorophyll and the cellular structures normally found in leaves. They use crassulacean acid metabolism (CAM), opening stomata only at night to absorb carbon dioxide, which is stored as malic acid and used the following day when the stomata close.
What is the oldest archaeological evidence of humans using cacti?
Seeds found in ancient middens in Mexico and Peru suggest human use of cacti going back 12,000-9,000 years. Cave paintings in the Serra da Capivara in Brazil also document early encounters with these plants.
What cactus produces peyote and how old is its ceremonial use?
Peyote comes from Lophophora williamsii, a small cactus native to northern Mexico and southern Texas. Evidence of ceremonial use stretches back more than 5,500 years; dried peyote buttons from a Rio Grande site in Texas were radiocarbon dated to around 3780-3660 BC.
Are all cactus species native to the Americas?
Almost all cacti are native to the Americas, ranging from Patagonia to parts of western Canada. The single exception is Rhipsalis baccifera, which also grows naturally in tropical Africa, Madagascar, and Sri Lanka.
Why is cactus scientific classification still unsettled?
Cacti resist standard botanical preservation because they evolved to resist desiccation, making type specimens hard to prepare. The classifier Curt Backeberg named approximately 1,200 species without attaching names to physical specimens, creating lasting confusion. A 2011 molecular study found that only 39% of genera sampled within the largest subfamily were monophyletic.