# Brain cactus



## TimV (Mar 13, 2010)

For those of you who remember basic geometry, the sphere is the shape with the smallest surface area in relationship to the size of the body. Therefore it is no surprise that many plants from dry areas have thicker leaves and stems than those from areas with more rainfall. After all, there is with a sphere less surface area for evaporation, so water is more easily retained.

But one of the prices a plant pays is that there is less surface area, so naturally the plant can make less food, as less chlorophyll is exposed to the sun.

The _Stenocactus_ family of cactus have a really tricky way of killing two birds with one stone. They have a spherical shape, but in addition, really crazy looking "ribs" which you can see if streched out, hugely expand the surface area of the photosynthetic parts of the plant. These ribs also channel water to the roots. Imagine a very light rain, or even mist. In a normal plant the water would mostly evaporate, but with the _Stenocactus_ even small droplets are channelled into the narrow valleys in the skin and accumulate enough to allow a few drops to flow right to the exact place that the plant can take it up.

Also, this family takes advantage of the fact that most other plants in the area flower in the spring and summer. These guys flower in the winter, so there's not much else for insects, bats, and other plants who feed on pollen and nectar to eat, and guess who gets all the attention for pollinators! And as an aside, they're nice in a collection, since there's always some blooms in the winter time if you have a couple species of _Stenocactus_! This one is _S. multicostatus_, commonly called the Brain cactus:


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## KMK (Mar 13, 2010)

Very cool!


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## MLCOPE2 (Mar 13, 2010)

It's beautiful too!


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## dudley (Mar 13, 2010)

Interesting post and beautiful flower. Very informative. In New Jersey we are beginning to see some pernial flowers just sprouting out of the ground this past week.


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