The ascocarps (_apothecia_) are at first closed, and _only open_ at the time of their ripening, not valvularly, but more or less like a _saucer_ or _cup_, so that the hymenium lies exposed on their upper surface. In the first three sub-families, and generally also in the fourth, the apothecia are formed inside the substratum. The apothecia are, in contrast to the Pyrenomycetes, light and brightly coloured, and their size varies very much, and may be several centimetres in diameter. Paraphyses are often present between the asci; they often contain colouring matter, and give to the disc its characteristic colour. The tissue on which the asci are borne is known as the _hypothecium_. The shape and colour of the spores is not so varied as in the Pyrenomycetes. The accessory forms of reproduction are conidia (sometimes of two forms), chlamydospores, and oidia. The family is divided into 5 sub-families. Sub-Family 1. =Phacidiales.= The apothecia are developed in the interior of the substratum, which they break through, and in general dehisce apically. The envelope is tough and black. Hypothecium inconspicuous; hymenium flat. Order 1. =Euphacidiaceæ.= _Phacidium abietinum_, on the leaves of _Abies alba_.--_Rhytisma_; the pycnidia are found in the summer on the green leaves, while the apothecia are developed on the fallen leaves and dehisce in the following spring. _R. acerinum_ causes black spots on the leaves of the Sycamore, and _R. salicinum_ on Willows. Order 2. =Pseudophacidiaceæ.= Sub-Family 2. =Stictidales.= The apothecia when ripe break through the substratum which forms a border round them. Hymenium generally saucer-shaped. Order 1. =Stictidaceæ.= _Stictis._ Order 2. =Ostropaceæ.= _Ostropa._ Sub-Family 3. =Tryblidiales.= The apothecia are embedded in the substratum in the early stages, and then are raised high above it. Hypothecium thick. Hymenium cup-shaped. Order 1. =Tryblidiaceæ.= _Tryblidium._ Order 2. =Heterosphæriaceæ.= _Heterosphæria patella_ on the dead stalks of Umbellifers. Sub-Family 4. =Dermateales.= The apothecia in the early stages are embedded in the substratum and then break through it, or are from the first situated on the surface of the substratum. Hypothecium thick. Order 1. =Cenangiaceæ.= _Cenangium._ Order 2. =Dermateaceæ.= _Dermatea._ Order 3. =Patellariaceæ.= _Patellea_, _Biatorella_, _Patellaria_. Order 4. =Caliciaceæ.= _Calicium_, _Coniocybe_, etc., on the bark of trees. Order 5. =Arthoniaceæ.= _Arthonia_ on the bark of several trees. _Celidium stictarum_ on the apothecia of _Sticta pulmonaria_.