4> SYNOPSIS OF BTUTTSTI SEAWEEDS. 



Sub-class IL RHODOSPEEMKS ob 

 CERAMIAXES. 



(Red* or Brown-red Seaweeds.) 

 Order 7. Rhodomelacbjb. Red or brown-red seaweeds, u-itl m 

 leafy or filiform, a/reolated or articulated frond, composed 

 of polygonal cells. Fruit double: 1. Conceptaclea (cerami- 

 dia) external, era/, or wm-shaped, with a terminal pore, 

 a, nl containing a tuft of pear-shaped spores: 2. 

 spon a immersed in distorted ramuli, or contained in proper 

 receptacles {called hert stichidia). 



* Frond flattened, piwnatifid. 

 X X XVI. Odontualia. 



** Frond filiform, wholly marticulate. 



XXXVII. Rhodomela. Branches coated with minute, 

 irregular cells. Apices not involute. 



XXXVIII. Bostrychia. Branches dotted; the surface 

 cells quadrate. Apices strongly involute. 



XXXIX. Rytiphlcea. Branches transversely striate, at 

 short distances. 



*** Frond filiform, partially or generally articulate. 



XL. Polysiphonia. Articulations of the ramuli two- or 

 many-tubed. Tetraspores in distorted ramuli. 



XLI. Dasya. Articulations of the ramuli single-tubed. 

 Tetraspores in lanceolate pod-like receptacles (Stichi- 

 dia). 



Order 8. Laurenciace^:. Rose-red or purple seaweeds, with a 

 cylindrical or compressed, rarely flat, linear, narrow, areo- 

 lated, inarticulate, or constricted and chambered, branching 

 frond, composed of polygonal cells. Fruit double : 1. Con- 

 ceptacles (ceramidia) external, ovate with a terminal pore, 

 and containing a tuft of pear-shaped spores : 2. Tetraspores 

 scatter"/ without order among the surface cells of the branches 

 and ramuli. 



* Frond solid. 

 XLII. Bonnemaisonia. Rose-red, excessively branched, 



distichous ; ramuli subulate, acute. 

 XLIII. Laurexcia. Purplish, yellowish, or reddish, pin- 

 natifid or pinnate ; ramuli obtuse. 



** Frond (at least the branchesj hoUow. 

 XLIV. Cheysymexia. Frond neither constricted nor 

 chambered. 



* See also Ulvacea and Oscillatoriacece among the Green A 



