r.ui;r.M i L< i. 1:. B6 



139. tenuissima (The Blender Laurencia); frond filiform, te- 

 rete, irregularly divided ; branches Long ;,,1( ' nrgate, clothed 

 with very slender, setaceous ramuli, which taper to the ' 

 and apex, 9rev. Jig, Brit. p. US. (Atlab, PL WMI. 



Alsidium tenuisaimnm, Ktz. Chondria tenuissima, Ag. Gigar- 

 tina tenuissima, La/mow, Fucus tenuissimus, Good, and 

 Woodw. 

 Hah. South of England and Ireland. On rocks and stones be- 

 tween tide-marks; generally in Bhallow pools, about half- 

 tide Kvcl. Annual. Summer. Verj rare. 

 Thifl is by much the most slender and delicate, as it |g 

 also the rarest, of the British species of Laurencia. Wher- 

 ever it grows it is generally found in tolerable abundance, 

 forming dense tofts, many of which will often be found in 

 the same pool. The favourite locality is in very Bhallow 

 tide-pools, fully exposed to the sun, and frequently situated 

 but a short distance below high-water marl : thus clearly 

 showing a partiality for warmth which marks the straggler 

 from warmer latitudes. In such situations it frequently 

 becomes much discoloured, the purple hue, which is natu- 

 ral to it, being exchanged for a greenish-yellow, at the 

 same time that the cellular substance is much softened. 

 J have received fine specimens from the shores of Tasma- 

 nia, where it appears to be not uncommon. 



XLIY. CHRYSYMENIA. 



140. clavellosa ( The clubbed Chrysymenia) \ frond gelatino- 

 membranaceous, verymuch branched in a repeatedly pinnate 

 manner, branches of various lengths, mostly distichous; 

 ramuli distichous or quadrifarious, attenuated at the base; 

 capsules conical, J. Ag, Medit.p. 107. (Atlas, PL XXX. 

 Fig. 136.) 



Chondrothamnion clavellosum, Kiz. C. confertum, I> A 

 Chylocladia clavellosa, Honk. Gastridium clavellosum, Lyngb, 

 G. purpurascens, Lyngb, Chondria clavellosa, Ag. Grigar- 

 tina clavellosa, Lamour. Fucus clavellosus, Turn. 

 !/>>/,. Atlantic shores of Britain. On rocks, Btones, and parasi- 

 tical On the -mailer Algffi near low-water mark ; also on the 

 Btems of LaminaruB i at a greater depth. Annual. Spring 

 and summer. 

 Chrysymenia clavellosa wsb first described by Mr. Tur- 

 ner, in the Birth volume of the ' Linnsean Transactions,! 

 where a figure is given, bul was known, as this author in- 



