MEETINGS. 109 



22nd September last, at Delancey. A specimen of a curious 

 plant — Xanthimn spinosum — occasionally found on ballast 

 heaps in various parts of England, Avas next exhibited. The 

 specimen in question was found by Mr. Derrick in September 

 last on the ballast heap near Bordeaux Harbour, and identified 

 by Mr. Marquand. 



But the main business of the evening was " A chat about 

 lichens," by Mr. E. D. Marquand, who for fourteen years has 

 made these one of his special studies. He dealt first 

 with the term lichen which has no common English 

 equivalent. Lichens are the most generally diffused class 

 of terrestrial plants on the face of the globe, and are 

 the pioneers of all other plant life. They occur from 

 the Equator to the Poles, and from sea-level to the 

 summits of the highest mountains ; but only where the 

 air is pure and circulating; they are essentially creatures 

 of light and clear atmosphere, as fungi are of dampness 

 and shade. Many species are cosmopolitan, though the 

 majority are peculiar to certain regions, such as mountains 

 or the sea coast. All their nutrition is derived from the 

 atmosphere ; their growth is exceedingly slow ; and their 

 duration of life is remarkable, extending sometimes to several 

 centuries. Lichens are closely allied to fungi, and both pass 

 gradually into the algae through certain genera which stand 

 on the border line, viz., Collema, Lichina, Nostoc, &c. Mr. 

 Marquand then fully described and illustrated on the black- 

 board the structure of a lichen thallus and its mode of 

 fructification — and roughly outlined the system of classifica- 

 tion. As a lichenologist of many years' experience he would 

 commend the subject to all who are in search of a fascinating 

 winter study. The lichen-flora of Guernsey is a particularly 

 interesting one, the maritime saxicolous species being especially 

 well represented. Most of the difficulties connected with the 

 study exist only on the threshold, and will speedily be over- 

 come by steady perseverance and determination. 



A large number of representative specimens were 

 exhibited, and examined by members at the close of the 

 lecture, which had been thoroughly enjoyed by all present. 



Monthly Meeting held on March 26th, 1891, Mr. E. D. 

 Marquand in the chair. 



The minutes of the last meeting having been read, the 

 Chairman exhibited a specimen of Atypus Sulzeri, one of 



