72 A SUPPLEMENT TO THE * FLORA VECTENSIS,* 



receive the full influence of the sun's rays, which certainly affects the 

 mean temperature. 



The Algic of the " Maidens," with few exceptions, have a wide rano;e in 

 latitude and louf^itude on the British and Irish coasts ; Alaria and Oclon- 

 thalia are chiefly confined to the Northern shores. 



As to the relation betvveen the kind of rock and the distribution of Alj?fe, 

 it may be sufficient to observe that the more abundant and widely diffused 

 are found indift'orently on rocks of the most opposite character; that 

 liabitat does, however, modify the composition of at least one common 

 species seems proved by the following instance. "VVlien passing the co;ist 

 at Bay of Nigg, near Aberdeen, in September last (1870), I observed an 

 iron chain newly brought to shore which had been during six months in 

 four to five fathoms water, it was completely covered by the Rhodi/mejiia 

 palmata ; attached to tliis chain there was a piece of hempen rope, about 

 three feet in length, which had a crop of Polyuphonia Brodirei ; these were 

 the only species, and each was strictly confined to the chain in the one 

 case, and to the rope in the other. The Polysiphonia was of good size, 

 nearly as large as it occurs on the neighbouring rocks ; the Rhodymema 

 was dwarf, two or three inches, paler and more delicate than usual ; of 

 the last I collected sulhcient for analysis, and am indebted for a report to 

 my friend and former pupil, J. C. Brown, D.Sc. Lond., and Lecturer on 

 Toxicology, Medical School, Liverpool ; he was very careful to avoid any 

 source of fallacy. 



Rhodymenia from iron chain, 

 Iron = 0-01 13 per cent, of dry plant, 

 or 0'235 per cent, of tlie aslies. 

 RJiodymenia from granite rocks. Bay of Nigg, 

 Iron = 00035 per cent of the dry plant, 

 or 0"056 per cent, of the ashes. 

 It can scarcely be that in this case each plant "selected" its special ha- 

 bitat; Rhodymenia is a common perennial species, the Polysiphonla appears 

 only toward the end of summer. The fishermen at the salmon station 

 assured me that chain and rope were quite clean when put into the sea; 

 it is probable that the piece of rope had been in some way bedded in sancl 

 or mud, which having been, towards the end of the season, washed away 

 by currents, the Polysiphonla grew on it, the chain having been previously 

 covered with a thick crop of the Rhodymenia. 



A SUPPLEMENT TO THE 'FLORA VECTENSIS.' 



By Alexander G. More, E.L.S., M.R.l.A. 



During the fourteen years which have elapsed since the publication, in 

 1856, of Dr. Bromfield's 'Flora Vectensis,' several plants have been 

 added to the list, and the discovery of many new localities for rare species 

 has rendered the botany of the Isle of Wight much better known. The 

 present seenis a good opportunity for bringing together various contribu- 

 tions received from other botanists, which, joined to the results of my 

 own observations during seven years' residence at Bembridge, from ISo'G 

 to 1862, will serve, in some measm-e, as a continuation of the successful 

 hibours of the late Dr. Bronifield. 



