What most people call pencil cactus is a spineless, multibranched euphorbia.
It's sap is indeed toxic if ingested and also a skin irritant, as is the sap of
most euphorbias, including poinsetta.

The experience is actually my wife's, and the pencil tree is the plant
described above. Our tree had grown to a large size and she decided to
propogate some of the smaller limbs and get rid of the main plant. She brushed
her lower leg against one of the cut trunks and then kneeled down,
transferring the sap to her upper leg also. She ended up with two whopping
sores that seemed to take about 2 weeks to heal.


Gary Brady
Austin, TX