Ser. Melanosperme^:. Fain. Dictyotea. 



Plate I. 



DICTYOTA ATOMARIA, Grev. 



Gen. Char. Root, a mass of woolly fibres. Frond flat, membranaceous, 

 ribless, reticulated, dichotomous or irregularly cleft. Fructification 

 consisting of scattered or clustered somewhat prominent seeds on both 

 surfaces of the frond. 



Dictyota atomaria ; frond broadly wedge-shaped, or somewhat fan-shaped, 

 deeply and irregularly cleft longitudinally ; seeds forming waved trans- 

 verse lines, with intermediate broken ones. 



Dictyota atomaria, Grev. Alg. Brit. p. 58. Hook. Br. Fl. vol. ii. p. 280. 



Wyatt. Alg. Damn. no. 60. Endl. 3rd Suppl. p. 24. Harv. Manual, p. 32. 



J. Ag. Alg. Medit. p. 37. Menegh. Alg. Ital. vol. i. p. 229. 

 Dictyota zonata, Lamour. Es. p. 57. 

 Dictyota ciliata, Lamour. Es. p. 58. 

 Zonaria atomaria, Ag. Sp. Alg. vol. i. p. 128. Ag. Syst. p. 264. Grev. Fl. 



Edin. p. 298. Gh-ay, Br. PI. vol. i. p. 341. 

 Padixa atomaria, Montag. Fl. Canar. PI. Cell. p. 146. 

 Padina phasiana, Bory, Fl. Pelop. p. 75. 

 Stypopodium atomarium, Kiitz. Phyc. Gen. p. 341. 

 Ulva atomaria, Woodw. in Linn. Trans, vol. hi. p. 53. Eng. Bot. t. 419. 

 Ulva serrata, BeCand. Fl. Fran. vol. ii. p. 11. Encycl. Bot. vol. viii. p. 166. 



Hab. On marine rocks, rare. Annual. Summer. At Cromer, Mr. Wigg. 

 Corton and Gunton, Mrs. Fowler. Worm's Head, Glamorganshire, 

 Mr. Dillwyn. Coast of Devon, Mrs. Griffiths. Sussex, Mr. Borrer. 

 Frith of Forth, Br. Greville. Ballycotton, coast of Cork, Miss Ball. 



Geogr. Distr. West Indies, Lamouroux. Canary Islands, rare, Bespreaux. 

 Mediterranean Sea, Agardh. German Ocean. Atlantic Coasts of France 

 and Spain. 



Desc. Root, a broad mass of woolly, entangled, brown fibres. Fronds clustered, 

 from 3 to 12 inches long, and from half an inch to 3 inches wide, delicately 

 membranaceous, translucent, pale olive-green above, becoming darker to- 

 wards the base, glossy, broadly wedge-shaped, variously cleft from the apex 

 downwards, sometimes very much jagged, never quite entire; the lateral 

 margins either entire or ciliato-dentate ; the tips of the lacinia^ truncate. 

 Seeds disposed in dark brown wavy transverse bauds, running across the 

 whole frond, at intervals of less than an inch, the spaces between more or 

 less densely mottled with broken lines or irregular spots of seed-. 



This beautiful plant was discovered towards the end of the 

 last century by Mr. Lilly Wigg, on the coast of Norfolk, and first 

 published in the third volume of the Linnacan Transactions by 



B 



