A small family, which is associated with and often included under Graphidaceae. The thallus is crustaceous and corticate on the upper surface, the cortex being formed of palisade hyphae. Algal cells _Trentepohlia_. Apothecia are rounded or with a tendency to elongation, and, in addition to a thin proper margin, possess a stout thalline margin; the hypothecium is thick and carbonaceous. There are two genera: _Dirina_ with twelve species has a wide distribution; _Dirinastrum_ is monotypic and occurs on maritime rocks in Australia. In both the spores are elongate-septate, differing only in colour: Spores colourless 1. Dirina Fr. Spores brown 2. *Dirinastrum Müll.-Arg. XXII. _ROCCELLACEAE_ The Roccellaceae differ from the preceding Dirinaceae chiefly in the fruticose thallus which is more or less characteristic of all the genera, though in _Roccellographa_ it expands into foliose dimensions and in _Roccellina_ is reduced to short podetia-like processes from a crustose base. The fronds—mostly long and strap-shaped—are protected in most of the genera by a cortex of compact palisade hyphae; in a few the outer hyphae are parallel with the long axis. The medulla is of parallel hyphae, either loose or compact. The algal cells are _Trentepohlia_. The apothecia are lateral except in _Roccellina_ where they occur at the tips of the short upright fronds, and only in _Roccellaria_ is there no thalline margin. They are superficial in all of the genera except _Roccellographa_, in which they are immersed and almost closed, recalling the perithecia-like fruits of _Chiodecton_ (sect. _Enterographa_). The spores are elongate, narrow, pluri-septate, and colourless or brownish, except in _Darbishirella_ in which they are ovoid, 2-septate and brown. The affinity of Dirinaceae and Roccellaceae with Graphidaceae was first indicated by Reinke[1045] and elaborated later by Darbishire[1046] in his monograph of Roccellaceae. The apothecia in some species of _Dirina_ are ellipsoid rather than round; in several genera of Roccellaceae they are distinctly lirellate, and in _Roccella_ itself some species have ellipsoid fruits. The fruticose thallus is predominant in Roccellaceae, but its evolution from the crustaceous type may be traced through _Roccellina_ which is partly crustaceous and only imperfectly fruticose. In most of the genera only one species is recorded. _Roccella_, represented by twelve species, is well known for its dyeing properties, and has a wide distribution. Like other Graphidineae they are mainly plants of warm regions, many of them exclusively maritime rock-dwellers. The following synopsis of the genera is the one given by Darbishire in his monograph.