Plate V. 



Fig. 17. DESMAEESTIA LIGULATA. 



Colovr. When growings a clear olive-brown; on exposure to tlie atmospliere, 

 a verdigris-green; wlien dry, sometimes yellow; sometimes a pleasant 

 green; semi-transparent. 



S'uhstancG. Delicately membranaceous. Becoming limp {flaccid) after exposure 

 to tbe air. Recovering itself wlien dry. 



Character of Frond. Flat; witli an obscure midrib towards tlie base; branched. 

 Brandling on each side of the stem; the branches branched again and 

 again (repeatedly pinnate). Branches and branclilets in pairs exactly 

 opposite each other,, and all tapering at each end. The whole frond 

 at one level as if cut out of paper (disticJioiis) . In youth the margins 

 of the branches are fringed with minute tufts of cobweb-like fibres, 

 which fall off as the plant advances in age. 



Measurement. From 2 to 6 feet long; width varies very much. 



Fructification. Not ascertained. 



Habitat. South of England; occasionally north-east (Filey). All round the 

 coast of Ireland. Between tide-marks, on rocks and stones. 



In the north-west of Ireland a variety occurs, which is sometimes from 1 to 

 2 inches wide; called D. Bresnaii by French botanists. 



Fig. 18. DESMAEESTIA ACULEATA. 



Colour. When fresh and young, stems green olive; tufts bright green; on 



exposure to the atmosphere, verdigris-green; v/hen dry, resuming its 



original hues. In age, brown. 

 Substance. Tender and membranaceous in youth. Becoming limp and sticky 



on exposure to the air. Becovering itself when dry. In age, harsh. 

 Character of Frond. Stem and branches. Stem very short; cylindrical. 



Branches long; very narrow; slender; flat; repeatedly rebranched. 



Margins, in youth, fringed with minute tufts of delicate bright green 



fibres; in age, with thorns. 

 Measurement. From I to 3 feet long. 

 Fructification. Not ascertained. 



Habitat. Our coasts generally. On rocks near low-water mark; common. 



A beautiful plant when young, from the bright green tufts which fringe its 

 margins; but ugly when old. All three Desmarestias should, during collection, 

 be kept apart from delicate red sea-weeds, as they possess some curious power 

 of decomposing their more fragile neighbours. 

 9 c 



