LAURENCIACE^,. 95 



and their divisions clothed with very slender, hair-like, dichotomous, single- 

 tubed ramuli. Colour a fine rose-red. Substance very flaccid and tender, 

 closely adhering to paper. A beautiful species, with the habit of Seirospora 

 Griffithsiana, more than of any British species of Dasya. 



Order VIII. LAURENCIACE^.* 



Lauvenciese, Hook. Jil. and Harv. Lond. Journ. vol. iv, 

 p. 539. Chondriese, J. Ag. Alg. Medit. p. 67. Harv. Ner. 

 Austr. p. 7. Lomentarieae, Endl. Sd Snppl. p. 42. Chon- 

 drieae (partly), Chondrosipheae, Cbampieae, Kutz. Phyc. Gen. 

 pp. 435, 438, 439. Lomeutareae, Lindl. Veg. King. p. 25. 



Diagnosis. — Rose-red or purple sea-weeds, with a cylin- 

 drical or compressed, rarely flat, linear, narrow, areolated, 

 inarticulate or constricted and chambered, branching frond, 

 composed of polygonal cells. Fructijication double: l,cow- 

 ceptacles {ceramidia) external, ovate, furnished with a termi- 

 nal pore, and containing a tuft of pear-shaped spores ; 

 2, tetraspores immersed in the branches and ramuli, scattered 

 without order through the surface cells. 



Natural Character. — Root sometimes a simple disk, but 

 very frequently branching. Frond mostly cylindrical, rarely 

 compressed, and still more rarely flattened, destitute of mid- 

 rib, linear, usually preserving nearly the same breadth through- 

 out, branching; the branches most generally pinnate, some- 

 times whorled, sometimes tufted, and sometimes (but very 

 rarely) dichotomous. In the typical genera (such as Lauren- 

 cia and Bonnemalsonia) the frond is solid, the whole substance 

 composed of polygonal cells closely packed together, and 

 there is no trace of articulation or regularly recurring con- 

 striction. But in some genera (as CJiylocladia, Cliampia^ 



* This order is usually called ChondriecB., a name objectionable on two 

 grounds. First, the genus Chondria, Ag., is suppressed, being synonymous 

 with Laurencia, L., the typical genus; and, secondly, the sound Chondrie<B 

 or Chondriacece recalls Chondrus, which is a genus belonging to Cryptone- 

 miacea. I therefore propose a name taken from the original, and most 

 widely dispersed genus of the order. 



