A HISTORY OF CORNWALL except in Jersey. One very rare species, Placodium fulgens, forms a zone of a golden yellow colour on a calcareous sand dune near Padstow, and also occurs on flat ground near Constantine Bay. The species common on old trees or old wood in drier countries are remarkable for the absence of records, especially the genera Calicium and Phlyctis. The species of the genus Pertusaria, though fairly repre- sented, do not appear to fruit so freely as in the Devonshire ravines. The Collemacei also, as might be expected from the absence of limestone, are not very numerous. Where limestone does occur however, as at Cremyll near Mount Edgcumbe, species characteristic of that formation, such as Placodium cirrhochroum, Lecanora ochracea, L. ca/carea, Verrucaria immersa, and V. conoidea, etc., are met with. The Gyropborei, which are fairly abun- dant on the Dartmoor Tors, are represented in Cornwall very sparingly, Umbilicaria pustulata and U. polyrrbiza only having been detected hitherto, the former at St. Breward, Helmentor, and Tremoran Hill, and the latter only near Helmentor. Lithographa dendrographa appears to occur much more sparingly than in Devon, but Stigmatidium circumscription is notice- able everywhere near the sea on the clay slate and the serpentine, growing often in the most provoking manner across the grain of the clay slate, so that it is almost impossible to get a good specimen. Although so large a proportion of the British lichen flora has been detected in Cornwall, there is little doubt that many rare species will yet be found on the maritime rocks and inland coppices, and possibly on old trees in some of the parks scattered through the county. The classification followed is that of Crombie's British Lichens as far as Urceo/aria and Leighton's British Lichen Flora from Lecanora to Melano- theca, the species being arranged alphabetically for facility of reference. The rarer species in the list are indicated by an asterisk. EPHEBACEI, Nyl. COLLEMACEI (continued) Sirosiphon compactus, Ktttz. W.C. Collema plicatile, Nyl. E.G. Gonionema velutinum, Nyl. St. Cher, var. hydrocharum, Nyl. W.C. B.C. pulposum, Ach. W.C. Ephebe pubescens, Nyl. B.C., Rough Tor var. pulposulum, Nyl. B.C. Lichina pygmaea, Lightf. St. Minver, tenax, Ach. B.C. B.C. ; Penzance, Scilly Isles Collemodium biatorinum, Nyl. Wadebridge confinis, Ach. Antony, B.C. ; Fal- fluviatile, Nyl. St. Minver mouthy Penzance Schraderi, Nyl. COLLEMACEI turgidum, Nyl. Wadebridge Collema cheileum, Ach., f. nudum, Nyl. Leptogium amphineum, Nyl. Penzance B.C. lacerum, Gray, f. fimbriatum, Hoffm. concinnum, Flot. Penzance B.C. crispum, Ach. St. Minver sub-sp. pulvinatum, Nyl. Hayle Sands sub-sp. ceranoides, Nyl. St. Minver, sub-sp. lophasum, Nyl. B.C. Penzance Scotinum, Fr. Hayle Sands f. cristatulum, Nyl. St. Minver muscicolum, Fr. Penzance flaccidum, Ach. Boconnoc, Came/ford, palmatum, Mont. Marden Woods near St. Minver Penzance furvum, Ach. Forth Burrow subtile, Nyl. Withiel glaucescens, Hoffm. B.C. tenuissimum, Koerb. Penzance granuliferum, Nyl. St. Minver tremelloides, Gray. St. Issey, Ruan nigrescens, Ach. Lizard, Penzance Minor, Lamorna 100
