Dictl/oieCE.'] DICTYOTA. 141 



Genus XYII. DICTYOTA, Lamour. 



"Nihil inutile, niliil vanum, nihil supervacaneuni in Xatura." — Bacon. 



Generic Character. Frond flat, reticulated, membranaceous, 

 dichotomous, or irregularly cleft (palmato-flabelliform in D. ato- 

 maria). Eoot, a mass of woolly filaments. Fructification com- 

 posed of scattered or variously aggregated, somewhat prominent 

 seeds, on both surfaces of the frond. — The name signifies net- 

 work^ in allusion to the reticulations of the frond. — Greville. 



1. DiCTYOTA DicnoTOMA, Lamour. (Plate 11. fig. 5, the 

 broad variety, and the small figure to the left is var. /3.) 



Hab. In the sea, on Algse, and in rock-pools ; very com- 

 mon. Annual. Summer and autumn. 



This plant is widely distributed over the world. On the 

 Ayrshire coast and in the islands of Arran and Cumbrae, 

 var. /3 is very common, the frond of which is narrow. 

 I have had very beautiful broad-fronded specimens from the 

 coast of Arg^deshire, gathered by Eev. Mr. Lambie at the 

 south end of Kintyre. Both kinds are well represented in 

 Plate cm. of 'Phycologia Britannica,^ but with us the 

 var. /3 is of a much darker colour. 



