The word cactus derives from the greek word κάκτος (káktos).
Cacti occur in a wide range of shapes and sizes. Many smaller cacti have
globe-shaped stems, like the smallest cacti, called
Blossfeldia liliputiana which is only about only about 1 cm in
diameter at maturity. On the other hand, the tallest cactus is the
free-standing Pachycereus pringlei, with a maximum recorded
height of 19.2m.🤯
Just imagine these two next to each other!
I always thought cacti have thorns, but as I was looking them up on
Wikipedia, it turned out I was wrong.
Botanically, "spines" are distinguished from "thorns":
spines are modified leaves, and
thorns are modified branches. Cacti produce spines,
always from areoles (which are a kind of highly reduced branch).
As well as spines, areoles give rise to flowers, which are usually
tubular and multipetaled.🌸
I would love to copy-paste some more from the original site, alas it
would be meaningless since there will be a link for curious minds for
more at the bottom.⏬⏬⏬