A number of genera, _Thamnolia_, _Siphula_, etc. are of podetia-like structure, generally growing in swards. Several of them have been classified with _Cladoniae_, but they lack the double thallus. One of these, _Endocena_, a sterile monotypic Patagonian lichen, with stiff hollow coralloid fronds, was classified by Hue[1056] along with _Siphula_; recently he has transferred it to his family Polycaulionaceae[1057] based on _Polycauliona regale_ (_Placodium frustulosum_ Darbish.), and allied to _Placodium_ Sect. _Thamnoma_[1058]. In recent studies Hue has laid most stress on thalline characters. He places the new family between “Ramalinaceae” and “Alectoriaceae.” _Dactylina arctica_ is a common Arctic soil-lichen. Thallus strap-shaped. Structure dorsiventral. Greyish-green above 1. Evernia Ach. Whitish-yellow above 2. *Everniopsis Nyl. Structure radiate alike on both surfaces. Fronds grey; medulla of loose hyphae 3. Ramalina Ach. Fronds yellow; medulla traversed by strands 4. *Letharia A. Zahlbr. Thallus filamentous. Medulla a strong “chondroid” strand 5. Usnea Dill. Medulla of loose hyphae. Spores simple 6. Alectoria Ach. Spores muriform, brown 7. *Oropogon Fr. Thallus of upright podetia-like fronds. Fronds rather long (about two inches), tapering, white 8. Thamnolia Ach. (Cerania S. F. Gray). Fronds shorter, blunt. Medulla solid 9. *Siphula Fr. Medulla partly or entirely hollow. Fronds swollen and tall (about two inches) 10. *Dactylina Nyl. Fronds coralloid, entangled 11. *Endocena Cromb. Fronds short, upright 12. *Dufourea Nyl. XLVIII. _CALOPLACACEAE_ In this family Zahlbruckner has included the squamulose or crustaceous lichens with colourless polarilocular spores, relegating those with more highly developed thallus or with brown spores to other families. He has also substituted the name _Caloplaca_ for the older _Placodium_, the latter being, as he considers, less well defined. Algal cells are Protococcaceae. The thallus is mostly light-coloured, generally some shade of yellow, and, with few exceptions, contains parietin, which gives a purple colour on the application of potash. The squamulose forms are closely appressed to the substratum, and have often a definite rounded outline (effigurate). The spores have a thick median septum with a loculus at each end and a connecting canal[1059].