Some Observations on Root-Parasitism in New Zealand By W. R. Philipson, University of Canterbury [Received by the Editor, June 26, 1958.] Abstract It is shown that the endemic genus Mida (Santalaceae) is a root-parasite, and this condition is confirmed for New Zealand species of Euphrasia and Exocarpus. Root parasites are rare among New Zealand flowering plants. The habit appears to have been recorded definitely for only one species—namely, Dactylanthus, a striking monotypic genus of the Balanophoraceae, which is confined to the North Island (Cheeseman, 1914 and 1920). It has been stated frequently in New Zealand botanical literature that the species of Gastrodia (Orchidaceae) are parasitic on the roots of other plants, but this is not correct; these orchids are saprophytic. Exocarpus Many members of the Santalaceae are known to be parasitic, and this habit has been recorded for Exocarpus in Australia. (Benson, 1910; Herbert, 1925; Rao, 1942). So far as is known no published report exists of parasitism in the single New Zealand endemic species, Eibidwillii. In a recent paper by Aiken (1957), for example, it is stated that no parasitic members of the Santalaceae are known from New Zealand. The following description of the haustoria in that species may therefore be of interest. The small shrub Exocarpus bidwillii is frequent at mid-altitudes on the mountains of the South Island of New Zealand. It attracts attention by its curious appearance: the densely branched erect twigs are reddish-brown and the leaves are reduced to minute scales. The root system is woody and usually runs underground for considerable distances, often among boulders. Sometimes, therefore, it has proved difficult, or impossible, to demonstrate haustoria. However, these have been observed in a sufficient number of cases to warrant the assumption that they are general or even invariable. The haustoria, when they are seen, are found in abundance, and may form such an intricate plexus of connections with several roots that the relations between parasite and host are difficult to interpret. This complexity is due to the finer roots of Exocarpus producing a close succession of haustoria when they are appropriately situated in relation to a host root. As in other members of the Santalaceae, young roots will attack large as well as fine host roots, the haustoria being capable of penetrating well developed cork layers. Sections through haustoria confirm that the tissues of the host are penetrated. A central peg of tissue projects into the host, but union remains superficial, contact being made with the secondary phloem but not, so far as has been observed, with the xylem. In this respect, therefore, the New Zealand species resembles E. spartea as described by Herbert (1925) rather than E. cupressiformis and E. aphylla described by Benson (1910) and Rao (1942) respectively. Roots of Exocarpus have been found with haustoria on Helichrysum selago. However, the range of hosts must be wide, as is the case in some other members of the Santalaceae, because Exocarpus has not been observed to associate constantly with this Helichrysum or with any other species. Mida The only other members of the Santalaceae occurring in New Zealand are the two species of the endemic genus Mida, both of which are confined to the North Island. Formerly this genus was united with Eucarya (Fusanus), a genus which