Polaskia chichipe

[echinopsis ed]

Yeah, I think cacti spines are not waterproof, but actually soak in water. Perhaps this helps to cool them in the desert heat?

Found this info on cacti spines.

Spines: Spines help the cactus in several ways. The most obvious use of the spines is for protection against foragers. The cactus basically states "How much pain are you willing to indure to get a drink in this desert?"; Surprisingly, some animals do partake. In some cactus varieties the spines participate in water collection. Water from dew condenses on spines and, in some cactus species, downward-pointing spines help to direct rainwater to the roots of the plant. Spines help to reflect light away from the cactus stem theoretically lowering the stem temperature. Some spines also trap in a layer of air next to the cactus stem preventing loss of water via evaporative cooling.?

[daiv]

Hmm. That certainly is in keeping with what I've observed, so I'd go along with it.

[Lewis_cacti]

Apparently Discocactus horstii has the unique ability to actually absorb water in the form of dew into the plant. Amazing! better get my seed going.