ORDERS AND GENERA. Vll 



XXXIII. Sphacelaria. Hamuli distichous, mostly pinnated. 



* * Frond Jlaccid ; each articulation formed of a single cell. 



XXXIV. Ectocarpus. Frond branching; ramuli scattered. 



XXXV. Myriotrichia. Frond unbranched ; ramidi whorled, and tipped with 

 pellucid fibres. 



Sub-class II. BHODOSPERMEJE OR OEBAMIALES. 



(Red* or Brown-red Seaweeds.) 



Order 7. Rhodomelace.e. Red or brown-red seaweeds, with a leafy or 

 filiform, areolated or articulated frond, composed of polygonal cells. 

 Emit double : Conceptacles(ceraniidia) external, ovate or urn-shaped, icith 

 a terminal pore, and containing a tuft of pear-shaped spores : 2. Tetra- 

 spores immersed in distorted ramidi, or contained in proper receptacles 

 {called here stichidia). 



* Frond flattened, pinnatifid. 



XXXVI. Odonthalia. 



* * Frond filiform, wholly inarticulate. 



XXXVII. Rhodomela. Branches coated with minute, irregular cells. Apices 

 not involute. 



XXXVIII. Bostrycii i.v. Branches dotted ; the surface cells quadrate. Apices 

 strongly involute. 



\.\XIX. Hytipiil^ea. Branches transversely striate, at short distances. 



* * * Frond filiform, part/ally or generally articulate. 

 XL. Polysipiionia. Articulations of the ramuli two- or many-tubed. Tetra- 

 spores in distorted ramuli. 



\ \A . Dasya. Articulations of the ramuli single-tubed. Tetraspores in lanceolate 

 pod-like receptacles {Stichidia). 



Order 8. Laurenc-iace^e. Rose-red or purple seaweeds, with a cylindrical 

 or compressed, rarely flat, linear, narrow, areolated, inarticulate, • 

 striated and chambered, branching frond, composed of polygonal cells. 



Fruit double: 1 . Concept acles (ceramidia) external, urate, with a ter- 

 minal pore, and containing a tuft of pear-shaped spores ; 2. Tetrasporea 

 scattered without order among the surface cells of the branci, 

 ramuli. 



* Frond solid. 

 \]A\. Bonnemaisonia. Rose-red, excessively branched, distichous; ramuli 

 Bubulate, acuti . 



\LIII. Laubencia. Purplish, yellowish, or reddish, pinnatifid or pinnate; ra- 

 muli obtuse. 



* * Frond {d least the branches) hollow. 



\ I A \ . Ch eii bi m i:\ i \. Frond neither constricted nor chambered. 



MA. Chylooladia. Frond (at least the branches) constricted at intervals and 

 chambered. 



Order 9. Corallinacea. Rigid, articulated, or crustaceous, mostly calca- 



purple when recnt, fading OH exposure to mith-white, 

 composed of Cells in which carbonate of lime is deposited in an organized 



form. Tetraspores tufted, contained in ovati or spherical oonceptaclea 

 ramidia) from ished with a terminal f 



Sec also Ulva* nd 



