A degree of taxonomic significance can be attached to the mycorrhizal associations of Lactarius clarkei for the forms associated with the two major ectotroph genera show small differences and are worthy of recognition as distinct varieties. Apart from length of cuticular hairs, var. aurantiorubra is microscopically indistinguishable from var. clarkei, and it is often difficult to separate dried specimens of the two varieties. In the field, however, var. aurantiorubra can be recognised by the more orange, pruinose to subtomentose pileus, pinkish tinted lamellae, pallid orange-yellow flesh, and its association with Nothofagus.

Under (1) N. fusca and N. menziesii. Nelson: Maruia, 23.iii.l966, J. A. McRobb, (holotype, PDD 26384); 23.iii.l966, R.F.R. McN.; (2) N. menziesii, Otago: Secretary Island, 10.ii.l960, R.F.R. McN.; Nelson: Little Wanganui, Blue Duck Creek, 13.L1968, R.F.R. McN.

The dry, pruinose, sombre coloured pileus

cuticular structure, and white latex indicate that this species belongs in sect. Plinthogali subsect. Fuliginosi as defined by Singer (1962), although Singer indicated that he was reluctant to include species with white spores in this section. In a monograph of the North American species of sect. Plinthogali, Smith and Hesler (1962) considerably expanded Singer's concept by the inclusion of species with white spores.

Lactarius sepiaceus is characterised by the dark brown pruinose to subvelutinate pileus and stipe, cream lamellae, and prominently apiculate spores with reticulate ornamentation.

Lactarius tawai can readily be accommodated in sect. Lactarius sub sect, lnsulsini stirps Insulsus, as defined by Singer (1962). In their treatment of North American Lactarii, Hesler and Smith (1960) transferred a number of species included in sect. Lactarius by Singer (1962) to the new sections Scrobiculatus and Crocei. The species of stirps Insulsus were not redisposed in this work,

Lactarius tawai may be recognised by the viscid, concentrically zonate pileus and the pink tinted, pallid ochraceous lamellae. It is the only species found in New Zealand with a zonate pileus.

There is some controversy over the correct name for this species and it is sometimes called Lactarius necator. The fungus described and illustrated by Bulliard (1791) as Agaricus necator was subsequently redescribed by Persoon (1801), and although Persoon referred to Bulliard's plate, there is little doubt that the fungus described by Persoon was not A. necator Bull. When the name was revalidated by Fries (1821), the description of A. necator agreed with that of Persoon but not with that of Bulliard. It appears that in revalidating A. necator. Fries misinterpreted the species. For this reason Bulliard's name has been rejected in favour of A. turpis Weinm. by most recent workers (Neuhoff, 1956; Dennis, et al. 1960). On the other hand. Singer (1962) considered that Fries misinterpreted Agaricus turpis Weinm. when he transferred the name in 1838, and cited the species as Lactarius necator (Bull. em. Pers. ex Fr.) Karst.

Lactarius turpis is an introduced species commonly associated with Betula pendula throughout the South Island, It is indigenous to temperate regions of the Northern Hemisphere where it is typically associated with birches. The species is considered poisonous by European mycologists. Pilat (1961) stated that it is poisonous when raw or poorly cooked, but is edible although not recommended when the latex is soaked out. Lactarius turpis is readily recognisable by the large, stoutly stipitate, drab olive brown or brownish black frutifications, discoloured lamellae, and extremely acrid taste. The purple discolouration of the pileus with KOH and NH4OH is also characteristic. The species was placed in sect. Lactarius subsect. Vietini stirps Necator by Singer (1962).