IOO 



[O. . /. fragilissima Lamx. 

 f. fragilissima Lamx. 

 f. cuspidata Lamx. 

 f. cyathifera Lamx. 

 ii. A. anastomosans n. sp. 

 V. Fronds flattened winglike with undulating border, or almost cylindrical with a narrow border 

 or sometimes none: rows of cells in central strand curved, above all in winged specimens, 

 not horizontal. Nodes of entire central strand and cortical layer as broad in most cases 

 as the frond but not swollen cushion-like. Conceptacles not or slightly prominent, half 

 immersed in the tissue of the frond: 



12. A. foliacea Lamx. 



VI. Fronds cylindrical. Nodes consist of central strand; cortical layer splits or takes part in 

 the formation of the node. Conceptacles prominent, half immersed or - - in old plants - 

 entirely sunk in the cortical layer: 



a. Node consists of one layer of cells of the central strand : 



13. A valonioides Vendo. 



b. Node consists of one layer of long cells and one layer of short cells of the central 

 strand and as a rule also of the cortical layer: 



14. A. verrucosa Kütz. (syn. A. cryptai'throdia Zan.). 



c. Node consists of two layers of cells of equal length, with oblique anticline walls, 

 cortical layer splits : 



15. A. rigida Lamx. 



d. Node of three layers of cells of equal length; cortical layer splits: 



1 6. A nodulosa Kütz. 



e. Node of three or more layers of cells, alternately one long and one short, or two 

 long and one short ; irregular. Cortical layer splits or partially takes part in the 

 formation of the node by secondary growth : 



17. A. dubia Kütz. 



I should like to add a few remarks for the clear understanding of some species mentioned 

 in this Key. 



To Amphiroa Beauvoisii (Lamx.) Born., which species includes according to Ardissone l ) 

 and BORNET ') : 



A. exilis Harv. 

 A. pustulata Mert. 

 A . co Dip la na ta Kütz. 

 A. po ly zona Mont. 

 A. algericnsis Kütz. 

 jst also be reckoned A. brasiliana Dec. All these plants have the same structure of node. 



Phycologia mediterranea 1883. 

 : E. Bornet. Les algues .11- 1'. K. A. SCH01 iboe. Paris 1892. 



