Several clumps of Hermodactylus tuberosa, a striking member of the Iris family, are now well established on the Limestone Rock Garden.
The unusual and sombre colouring give rise to the ominous common names of black widow iris and snakeshead iris. Flowers appear singly from grassy, grey-green foliage, the petals a jaundice yellow and patched with a purple-brown moleskin on the falls.