Tuesday, November 13, 2012

Pensive Tuesday: Mysterious Trichomes!

Lithops and other succulents conserve water using many ingenious methods. They can quickly grow fine roots to pull infrequent rain into their succulent leaves. They use CAM photosynthesis to prevent water loss. They have tough skins that resist evaporation. They can be dormant for months and need no moisture at all. They can use their longer taproots to literally pull themselves underground.

But how do Tillandsias do it? Well, they also use CAM photosynthesis. But Tillies have a unique contraption to hold and keep water. The trichome.

from Bromeliad.org.au
Many plants other than bromeliads use a variety of trichomes for a variety of functions, but the Tillandsia trichomes are my subject today. They look  like flowers or shields on the surface of the leaves. The top-facing trichomes are different from those on the undersides of leaves. Tillandsias facing more sun and drought have more of them, and are more silvery/fuzzy as a result. Shady Tillies that are used to more moisture have fewer trichomes, and they look more green and smooth.

from botany.cz

T. magnusiana has lots of trichomes!

Tillandsia trichomes can open and close like trapdoors. They can reflect up to 45% of sunlight, keeping the plant cool and moist, and they can quickly pull in water from either fog or rain.  When this happens, they essentially "lock" to prevent the water from escaping. The plant turns green, and soaks up some sun. Good air circulation resets the trichomes and the cycle can begin again. Amazing!

A mix of Tillies, a mix of trichomes.


  1. Great post and pictures, Marla. Thank you for this information. Gail

  2. Thanks, Gail! The more I learn about these water-conserving plants, the more fascinated I become!

  3. Great post Marla! Tillies are such special, cool & weird plants. :)

  4. Great post, Marla. I have 2 of these fun little plants and have noticed that during the time that I have had them the white fuzz (trichomes?) has increased tremendously. If I give them more more sun and water with the white fuzz lessen? I prefer the way the they looked without the white fuzz. Thank you.

  5. It depends. It could be that your Tillies were young when you bought them, and silver is their mature color/form. But no matter how many trichomes, regular mistings (twice a day is good) will tend to give the plants a smoother, greener appearance. And bucket waterings (or hose sprays if they are outside) two or three times a week are ideal. Hope that helps!