Nuytsia floribunda - Philipps-Universität Marburg - Fb. 17

The haustorium (contact organ of parasitic plants) of Nuytsia floribunda (Loranthaceae) has the unique feature of a hard, clip-like fork, functioning like a guillotine in order to cut the host root into two parts. During the development the haustorium clings around the host root, such serving as an abutment (Widerlager), and then drives the sclerenchymatic, two-pronged fork through the host root. On the picture, the fork already did its job. The hole above the fork indicates where the host root has been.
This phenomenon is published in Beyer, Forstreuter and Weber (1989): Anatomical studies of haustorium ontogeny and the remarkable mode of penetration of the haustorium in Nuytsia floribund (Labill.) R. Br. Bot. Acta 102:229-235.