Exhibitions, Session 1885-86. 493 



3. Note on Pertiisaria (jlohuUfera. — This species is so rarely seen 

 in fructification that it may be interesting to state under what 

 conditions the fruit is produced. It is generally to be found on 

 oak trees in mossy woods, among boulders where a mountain stream 

 runs near by. The fruit is almost always found on patches near the 

 ground, rarely higher up on the trunk, and then only in ravines 

 where there is frequent mist and rain. I may here mention that 

 the Pertnsarias are easily recognised by chemical tests in the barren 

 state, but it is necessary to be careful in using the chlorinated lime 

 test. This should always be made, never bought ready made, for the 

 reason, that to make the solution stronger for disinfecting purjjoses, 

 chlorine gas is sometimes passed into it. Solution so made gives 

 no reaction with lichens. It should be made by filling a bottle one- 

 third full of chlorinated lime in drj/ powder, filling up with water, 

 shaking the bottle, and pouring off the supernatant liquid. The 

 solution should be made fresh when required, as it soon loses its 

 power of giving the necessary reactions if kejDt long. To ascertain 

 whether the solution is still active, the best test is a piece of the 

 barren thallus of Pertiisaria velata, which gives a beautiful carmine- 

 red the moment it is touched with chlorinated lime solution. I 

 always keep a piece on purpose to ascertain the goodness or other- 

 wise of my test solution. 



4. Note on Lithographa dendrographa, Nyl. — This species appears 

 also, like Eoccella, to find its northern limit in the south of England 

 It was found in Britain first by Dr IIoU, at Totnes, South Devon. 

 Subsequently, Mr "W. Curnow of Penzance detected it at Menheniot, 

 in Cornwall. I have since found it in abundance near Stoney Cross, 

 in the New Forest ; near Studland, Dorset ; near Sidmouth, Devon ; 

 and scattered widely around the shores of Torbay, from Watcombe 

 to Brixham, It frequently occurs in company with Lecidea carneo- 

 lutea, Turn., a very pretty species, of which I also send specimens, 

 and which likewise seems to be a southern species in Britain. 

 Lithographa dendrographa is easUy recognised when growing by its 

 broicnish, tliin thallus, and by the raised, rigid, polished margin of 

 its lirellce. Opegrapha vxdgata has a whitish thallus, and less 

 prominent margins to the lirella?. The spores are simple in L. 

 dendrographa. It almost always occurs on elm trees, rarely on ash, 

 and grows usually at a height of from 5 to 10 feet from the ground. 

 It was first described by Nylander in 1864. 



5. Note on RocceUa phgcopsis, — This lichen being so entirely a 

 southern species — so far as records go — a few remarks concerning 

 it may be of interest to botanists in Scotland. It extends, accord- 

 ing to the records given in Leighton's Lichen Flora, from the 

 Channel Islands to the Isle of Wight on the east, and the Devon. 



TKANS. BOT. SOC. VOL. XVI. 2 K 



