Another piece of the equation to keep in mind is how succulents receive sunlight, because there's a catch-22 here. They're often reducing their surface area to minimize water loss, especially in the stem succulents, but they're also reducing how much sunlight they can catch to motor their photosynthesis. This is why many succulents have such fun shapes -- rippled and ridged surfaces, crazy knobs and lumpy protrusions. These extensions, as well as adaptations to the stems, increase their ability to process sunlight, helping some types of succulents hang on. The shapes of succulents also typically vary depending on how much water the plants currently contain -- they expand when water is plentiful and contract when it's not. In some, ties with roots and other growths are severed when times get tough. Succulents can't afford to get sentimental.
When discussing succulents, it's important to understand how all the extensive adaptations they underwent to survive where water is scarce impacted them across the board. Their special metabolism and distinctive shapes are two aspects. Another example is how they grow. Many grow low to the ground -- practically burying themselves in order to avoid the harsh sunlight. Others are all about the shade; they enjoy living in someone else's shadow, especially if it's a well-placed rock or other form of shelter. Their rate of growth is also affected in several ways. For instance, plants get nutrients from the soil. (Ever buy a bag of fertilizer? Then you know what we're talking about.) But beyond that, plants need moisture to soak up all those yummy nutrients. This means that in terms of growth, succulents are the turtle in the race, not the hare. But hey, whatever works, right?
Another important factor with succulents is protection. Succulents are basically botanical water bottles, they thrive where others thirst. So how do they defend themselves against the dehydrated masses? If you've ever had the misfortune of bumping into a cactus, you've had a preview of how they pull this off. Spines and spikes, thick armored skin, yucky and sometimes poisonous juices are all among the defenses succulents have developed to keep meddlers away. Some of these protective measures even double up as rainwater collection devices -- like hollow spines that can slide water right inside.
In a rough-and-tumble environment, with the necessities for life few and far between, getting together for a date can be a bit of a challenge. Another way succulents are set up to survive is that many are self-propagating, whether through seeds or actual little plants all ready to go. Also, if you knock a chunk off a succulent, that piece can typically take root and start growing on its own fairly easily -- handy if the plant is in a place that suffers strong weather.
Whichever way you look at it, succulents are well armed to live days, months, and sometimes even years without a single fresh sip of water. They might not look like some of their non-succulent relatives, but they've got the right stuff to live where water is scarce. On the next page, you'll find lots more links about water, weather and all sorts of plants.