Page:VCH Warwickshire 1.djvu/95

 BOTANY THE LICHENS (Licbenes] Very little is known as to the distribution of the lichens in War- wickshire. The records of the elder botanists are few, are in some in- stances doubtful, and can rarely be received with confidence, except when they treat of the more readily recognized species. The natural and artificial conditions prevailing in the county are not indeed favourable to a rich lichen flora. Lichens naturally depend on light and pure atmospheric surroundings for their existence or full development ; and being of slow growth they cannot attain maturity under conditions of frequent interference, from the surface alterations that are inseparable from thickly-populated manufacturing districts. In a contaminated atmosphere or in shady crevices these plants will not come to perfection, but will assume the form of a Lepraria, which is an abnormal condition of many of the lichens. The yellow powdery and white patches com- mon on *oaks are examples of this state. Still in those portions of the county remote from large towns many of the more common species occur in abundance. On the trees a rich growth of Ramalina fraxinea, Parmelia caperata and Physcia ciliaris ; on heathy footways tiny forests of Cladonia pyxidata or C. cornucopioides ; on the stone coping of walls and bridges grey masses of Lecanora atra or Lecidea lucida ; in damp woods Cladonia digitata or the more common Peltigera canina ; on old palings Parmelia olivacea and Usnea barbata, and on old walls and slated roofs the golden fronds of Physcia parietina, every sort and condition of habitat being the home of one or other of the lichens. The following list is an incomplete record of the Warwickshire lichens : Collema crispum (Huds.) nigrescens (Huds.) Leptogium lacerum (Ach.) - fragrans (Sun.) Sphinctrina turbinata (Pers.) - anglica (Nyl.) Calicium phaeocephalum (Borr.) - trichiale (Ach.) var. ferrugineum (Borr.) - hyperellum (Ach.) - trachelinum (Ach.) - quercinum (Pers.) - curtum (Borr.) subtile (Pers.) Coniocybe furfuracea (Ach.) Trachylia tympanella (Fr.) Cladonia cervicornis (Schar.) - alcicornis (Flk.) pyxidata (Fr.) var. fimbriata (Hoffm.) furcata (Hoffm.) squamosa (Hoffm.) cornucopioides (Fr.) digitata (Hoffm.) var. macilenta (Hoffm.) Cladina sylvatica (Hoffm.) Cladina rangiferina (Hoffm.) - uncialis (Hoffm.) Stereocaulon paschale (Ach.) Usnea barbata f. florida (L.) / hirta (L.) f. plicata (L.) Alectoria jubata (L.) lanata (L.) Evernia furfuracea (Mann.) prunastri (L.) Ramalina farinacea (L.) fraxinea (L.) fastigiata (Pers.) Cetraria aculeata (Fr.) Platysma glaucum (L.) Peltigera canina (L.) rufescens (Hoffm.) Stictina scrobiculata (Scop.) Sticta pulmonaria (Ach.) Parmelia caperata (L.) olivacea (L.) physodes (L.) ambigua (Wulf.) perlata (L.) tiliacea (Ach.) var. scortea (Ach.) 57