A HISTORY OF STAFFORDSHIRE Lecidea uliginosa, Schrad. coarctata, Sm. rivulosa, Ach. contigua, Fr. f. leprosa (Leight.) f. flavicunda (Ach.) calcivora, Ehrh. canescens, Dicks. myriocarpa, DC. alocizoides, Leight. chalybeia, Borr. grossa, Pers. caeruleonigricans, Light. denigrata, Fr. tricolor, With. Ehrhartiana, Ach. diluta, Pers. Caradocensis, Leight. - incompta, Borr. - alboatra, Hoffm. f. epipolia (Ach.) - aromatica, Sm. - carneo-lutea, Turn. - umbrina, Ach. pachycarpa, Dur. - milliaria, Fr. - sabuletorum, Flk. - premnea, Ach. - carneola, Ach. - endoleuca, Nyl. rubella, Ehrh. geographica, L. - petrza, Wulf. - concentrica, Dav. - cupularis, Ehrh. - trucigena, Ach. - Parmeliarum, Smrf. - parasitica, Flk. Opegrapha herpetica, Ach. /. rubella (Pers.) /. rufescens (Pers.) atra, Pers. Turneri, Leight. varia, Pers. /. notha (Ach.) f. diaphora (Ach.) vulgata, Ach. Leightonii, Crombie lyncea, Sm. Stigmatidium crassum, Dub. Arthonia lurida, Ach. astroidea, Ach. Swartziana, Ach. pruinosa, Ach. Graphis elegans, Sm. scripta, Ach. var. serpentina (Ach.) var. pulverulenta (Ach.) inusta, Ach. sophistica, Nyl. Endocarpon miniatum, L. hepaticum, Ach. Verrucaria epigea, Ach. Dufourei, DC. nigrescens, Pers. glaucina, Ach. - viridula, Schrad. rupestris, Schrad. conoidea, Fries gemmata, Ach. epidermidis, Ach. - biformis, Borr. - chlorotica, Ach. f. trachona (Tay.) nitida, Weig. THE FRESHWATER ALG^ The freshwater algas are universally distributed and are to be found in every situation where moisture exists, amid the most deleterious surroundings or where the atmospheric conditions are good and health- ful ; ' on damp walls and palings, on soil heaps, damp earth, pathways, roadsides ; on wet rocks, stones in streams, in every ditch and water- course ; in canals, ponds, and attached to the various aquatic plants therein, in puddles, and the hoof holes of cattle in boggy places,' etc. The green dust-like growth on tree trunks, palings and old walls is one of the lower forms of alga?, Pleurococcus vu/garis ; in nearly every ditch one or other species of Vaucheria may be found ; old canals are frequently covered with the yellowish green masses of Enteromorpba intestinalis, and many of the old clay holes in the coal districts are rich in species of Nostoc and Conferva. The bogs, pools and watercourses of the Cannock district yield many of the more rare and beautiful species, as Chcetophora 68
