The cylindrical leaves of Caputia scaposa var. scaposa, sometimes called the silver spider and earlier Senecio scaposus, grow densely clustered on short branches. Especially when young they are covered in a woolly layer of silver-white hairs. Leaves curve inwards slightly to pointed tips, shaping the spidery likeness. Leaf dimensions are 10 cm long, 1 cm wide.

Where the felted leaf covering is damaged the dark green leaf surface becomes visible. A dense woolly covering on top of plentiful leaf succulence appears like overdoing the survival strategy, a belt and braces approach. The plant’s habitat is challenging, however, and an effective strategy is its own justification.

Water is not the only consideration in this: Sunburn is commonly prevented by hairs, the absence of which led to the invention of sun-block lotions, not needed by mammals barring one species. And now we learn that our sunblock causes damage in the sea and rivers (Vlok and Schutte-Vlok, 2010; iSpot; http://www.llifle.com/; www.cactus-art.biz).