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True Nature Filter


Water capture

When I sat down to write this post about a plant that has adapted to capture water in dry climates, I realized I didn’t know exactly which plant this was. I snapped the photo at a cactus farm in Tucson, AZ and forgot to take a picture of its label. Oops! Lesson learned. However, my mistake led me to find out something cool about coevolution.

 At first I assumed this spiky beauty was a type of agave, and I began to scan through Google for images, hoping one would match this plant so I could learn its species name. Yet, no picture on Google looked right.

Then I started to wonder if it could be a type of aloe. Still, none of Google’s aloe pictures matched mine either. I didn’t have much to go off of (there are many species of agave and aloe). Since I took the picture at a cactus farm that grows plants from around the world, I didn’t even have a geographical range to help narrow my search.

To complicate matters further, I learned that agave and aloe, while not actually related at all, are an example of convergent evolution – the process of similar traits evolving in completely different species of plants or animals from different taxonomic families, even when they exist in different regions of the globe. Another blogger has already gone into some of the science behind this fascinating relationship between aloes and agaves in more depth, so I’m going to let you read that great post if you’d like.

Eventually it occurred to me to call the cactus farm and ask them to identify the plant in the picture. It’s an aloe! Aloe brevifolia.

What I originally set out to marvel at in this post is the way this Aloe brevifolia (and other aloes and agaves, too) is shaped. The leaves near the top of the plant are reaching up to the sky, just waiting for the rain. They are even curved inward like a slide, making a perfect chute through which to guide drops of water down toward the aloe’s roots.

The first thing I thought as I came across this picture in the album from my trip was, What an ingenious invention for a thirsty plant! What is even more incredible, however, is the power of evolution to shape aloes to be such good water capturers – in the same way it shaped agaves and other plants that acquired a similar structure through convergent evolution.


Special thanks to B&B Cactus Farm in Tucson, AZ for getting right back to me with the I.D. for this beautiful aloe. They have some awesome plants, and I was in Paradise the whole time I was there! 

Lucia Hadella