The genus was confirmed as distinct and monotypic by Nickrent et al. (2010) who placed it as sister to monotypic Nanodea, within a new family, the Nanodeaceae.

Mida salicifolia is a small but long-lived tree, endemic to Aotearoa / New Zealand where it occurs on Te Ika a Maui / North Island, from North Cape to Wellington but scarce south of the Waikato and Bay of Plenty. A few trees are also recorded on offshore Islands of North Island, including on Aotea / Great Barrier Island, Hauturu-o-Toi, Little Barrier Island and Kapiti Island. The population is estimated at 20,000–100,000 mature individuals spread over coastal to montane forests of the North Island, but there has been a major contraction in geographic range, and as a result population, due to forest clearance. Considering the range reduction to the species within the last generation of the species, and continuing threats to this tree from invasive animal browsing it is suspected that the population will decline by at least 50% over three generations (1820–2120). It is assessed as Endangered.

This species is endemic to Aotearoa / New Zealand where it occurs on Te Ika a Maui / North Island, from North Cape to Wellington but scarce south of the Waikato and Bay of Plenty. A few trees are also recorded on offshore Islands of North Island, including on Aotea / Great Barrier Island, Hauturu-o-Toi, Little Barrier Island and Kapiti Island.

De Lange et al. (2018) estimated a population of 20,000–100,000 mature individuals spread over coastal to montane forests of Te Ika a Maui / North Island. There has been a major contraction in geographic range and, as a result population, due to forest clearance. The current major threat, leading to continuing population decline is animal browsing, especially from possum (Trichosurus vulpecula), which is an issue throughout this species' range. Mida is only common in localities where possum are absent (Waiheke and Aotea / Great Barrier Island) or heavily controlled. In other sites the species is declining as possums target the foliage, flowers, and fruits, browsing plants so heavily that in time they are killed. As possum numbers have increased, in sites where they are not controlled, or ineffectively, Mida has become scarce.

Considering the range reduction to the species within the last generation of the species, and continuing threats to this tree from invasive species it is suspected that the population will decline by at least 50% over three generations (1820–2120).

Mida salicifolia is small, hemiparasitic tree reaching eight or more metres tall (de Lange 2023). Plants are root parasites, attaching themselves to a range of mostly conifer hosts including Agathis australis, Dacrydium cupressinum, Phyllocladus trichomanoides and P. toatoa. Between September and November this species produces small, greenish, or pink-tinged flowers, with the fleshy fruits developing between October and February (de Lange 2023). Mida, due to its varied host preferences may be found in coastal to montane forest, though it seems most common in lowland and coastal forest. In sites without possum (Trichosurus vulpecula) or with possums in dwindling numbers it is often very common usually as the subcanopy within conifer dominated indigenous forest.

Undoubtedly there was major range contraction as a consequence of historic forest clearance. However, the main threat to this species is animal browsing, especially from possum (Trichosurus vulpecula)), which is an issue throughout this species range. Mida is only common in locations where possum are absent (Waiheke and Aotea / Great Barrier Island) or heavily controlled. In other sites the species is declining as possums target the foliage, flowers, and fruits, browsing plants so heavily that in time they are killed. As possum numbers have increased, in sites where they are not controlled, or ineffectively, Mida has become scarce.

This is a hemiparasitic species that is difficult to grow requiring attachment to the roots of a suitable host. It is very scarce in cultivation.

The main threat to Mida is possum browsing. Within the range of this species, in sites where possums are absent Mida is very common, and, provided there are a few mature fruiting trees left, in remnants where possums have been eradicated or heavily controlled, Mida readily regenerates and recovers its past abundance. Therefore, effective possum control is the key to maintaining and enhancing Mida populations, with the added benefit that other species palatable to possums also recover.

New Zealand Threat Classification System assessed this species as ‘At Risk / Declining’ Qualified ‘DP’ [Data Poor] (de Lange et al. 2018) citing criterion B1 viz., ‘large population with low to moderate ongoing or predicted decline (10–50%) and 20,000–100,000 mature individuals’.