The inflorescences of Pycnostachys urticifolia, the hedgehog sage or ystervarksalie (porcupine sage) in Afrikaans, grow in densely flowered conical spikes at stem tips. The generic name, Pycnostachys, is derived from the Greek word pyknos meaning dense and stachys meaning spike or ear of corn (wheat), descriptive of the inflorescence.

The unopened buds above the open flowers in the spike often have a pinkish colour, the one in picture showing this only at its tip. Below the open flowers on the spike where only calyces around the developing ovaries remain, the explanation of the origin of the common names of hedgehog sage and ystervarksalie stares one in the face:

The hairy calyx has five spiny points or teeth that become up to 1 cm long. When only this bristly calyx remains, the withered corolla having dropped off, the animal likenesses of these common names are warranted. Teeth serve as such an important detractor to enemies in the animal world; here the spines amount to the same, warning leaf browsers against eating the stem tips.

The spiny calyx teeth start off green, but may turn red gradually, remaining on the plant for many months, protecting the plant's important product, its seed (Onderstall, 1984; Manning, 2009; www.plantzafrica.com; www.zimbabweflora.co.zw).