LAURENCIACE^. 75 



9. Laurencia tuberculosa, J. Ag. ; " rosy purple, frond compressed, distichously 

 decompound-pinnate ; pinnte on a straight, excurrent rachis, alternate, patent ; the 

 medial pinnules siinilar, the lower short, transformed into roundish, tuberculated 

 warts, bearing tetraspores lodged in the tubercles." J. Ag. Sp. Alg. %p. 760. 



Hab. Vera Cruz, Liebman. 



" Frond 4 — 6 inches long, as thick as a pigeon's quill, sub terete or slightly com- 

 pressed, alternately and distichously bi-tri jiinnate ; rachides scarcely conspicuously 

 flexuous, obtuse, prolonged, naked beyond the pinna;. Primary pinna? 3 — 4 inches 

 long, secondary an inch and half." 



II. CHAMPIA. Desv. Harv.ref. 



Frond terete or compressed, branched, tubular, constricted at intervals, and 

 furnished internally at the constrictions with transverse membranous diaphragms 

 which divide the tube into chambers ; diaphragms connected by a few longitudinal, 

 confervoid filaments ; walls of the frond composed of polygonal cellules, in one or 

 many rows. Conceptacles ovate, with a terminal pore. Placentce one or many, 

 basal, much branched, confervoid, connected with the walls by confervoid threads, 

 and bearing on the ends of the branches densely crowded ovoid or obconic spores. 

 Tetraspores tripartite, scattered through the superficial cells of the branches and 

 ramuli. 



The genus now called Champia was founded in 1 804 by Thunberg under the 

 name Afertensia, a name previously given by Dr. Roth (1797) to a well-known 

 Boragineous plant of North America. Thunberg's original species, Ch. lumbricalis, 

 a native of the Cape of Good Hope, remained for about thirty years the sole mem- 

 ber of the genus ; but recently two others, C. compressa from the Cape, and C. 

 Tasmanica from Van Dieman's Land, have been added. These three constitute the 

 genus Champia as generally understood by algologists, and as it appears restricted 

 by Prof J. Agardh in his Sp. Alg. vol. 2, p. 3G8. I venture now to add to them 

 such species of Lomentaria of authors {Chylocladia of Greville and other Britisli 

 writers) as have ovate conceptacles furnished with a terminal pore ; because I find, 

 on carefully examining their sporaceous nucleus, that it is formed exactly on the 

 type of that of Champia lumbricalis, and not at all as in Lomentaria lallformis, the 

 type of the true Lomentaria?. In our Ch. parvida and Ch. salicornoides the placenta 

 is less paniculate than in Ch. lumbricalis, but nevertheless is much branched, as 



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