ETYMOLOGY: from the Maori language, pureke (pu.re.ke) = knob, refers to shape of paraphysis apex.

Pureke has all the features typical of the family Rhytismataceae (sensu Cannon & Minter 1986), and within the family is characterised by the following features:
- ascomata elliptic in outline with a single, longitudinal opening split;
- ascomata subepidermal;
- the ascomata develop a darkened lower wall at an early stage in ascomatal development, before the differentiation of paraphyses or the development of a darkened upper wall;
- in unopened ascomata the upper wall is mostly composed of dark, thick-walled cells, but has a line of pale, thin-walled cells along the future line of opening;
- in opened ascomata a layer of thin-walled, cylindric cells develops across the exposed face of the broken upper wall.
- paraphyses persistent, swollen, knob-like at the apex;
- asci clavate-stipitate, developing sequentially.

The generic description is based on features associated with the development and anatomy of the sterile tissues of the ascomata. As discussed by Johnston (1990) these characters are considered more useful for defining "natural" groups within the Rhytismataceae than ascospore shape, traditionally used at the generic level in this family.

Pureke is similar to Hypoderma (sensu Johnston 1990) in macroscopic appearance of the ascomata, ascus shape, and ascospore shape, but differs from Hypoderma in three of the nine characters listed by Johnston (1990) as important at the generic level. The ascomata of Pureke are subepidermal rather than subcuticular; in unopened ascomata, the zone of pale cells along the future line of opening extends all the way through the wall, rather than being confined to the inner part of the wall; and the paraphyses are swollen-clavate at the apex rather than unswollen.

Because of the importance other authors have placed on ascospore shape in the taxonomy of the Rhytismataceae, I will compare Pureke to other genera in this family with bifusiform ascospores. The three conifer-inhabiting genera with bifusiform ascospores, Bifusella Höhnel, Isthmiella Darker, and Solleela Darker, all have ascomata lacking a darkened lower wall, lacking differentiated cells along the edge of the opening split, and either lacking paraphyses or having paraphyses undifferentiated at the apex. Their asci are saccate to subsaccate in shape, and are often synchronous in development. Two other genera with bifusiform ascospores, Duplicaria Fuckel and Bifusepta Darker, are found on Ericaceae. Duplicaria has circular ascomata with radiate opening splits, the upper wall of the ascomata with no internal differentiation, and no differentiated cells along the edge of the opening split, saccate to subsaccate asci, and paraphyses undifferentiated at the apex. Bifusepta occurs on wood, has a very thick lower wall, and a distinctive upper wall structure, as discussed by Powell (1973).