Also pincushion distortion and lateral chromatic aberration are noticeable. These include king protea, sugarbush, tree pincushion and golden cone bush ("Leucadendron laureolum"). A biscornu is a small, octagonal, stuffed ornamental pincushion. In other words, it is a lens with little or no barrel or pincushion distortion. Common names include pincushion, coral bead or bead plant. Where the varieties of the pincushion cactus meet, they intergrade. However, this will upset focus and aberration optimization, and introduce pincushion distortion. The common name "pincushion cactus" refers to this and the closely related genus "Escobaria". Other kinds of aberration include "field curvature", "barrel " and "pincushion distortion", and "astigmatism". The ornamental pincushion is pollinated by birds. The genus "Mammillaria" also contains "pincushion" and other cacti. Another common name for members of this genus is pincushion flowers. These "radial distortions" can usually be classified as either "barrel" distortions or "pincushion" distortions. Porcelain pincushion dolls, or half-dolls, were fashionable in late 19th-century Europe, and remain collectable today. Robin in Robin's pincushion refers to the woodland sprite of English folklore, Robin Goodfellow.