96 SPH.EROCOCCOIDE^. v. 



6. Delesseria corymhosa, J. Ag.; "frond subfiliform, dichotomo-corymbose, the 

 upper segments linear, obtusely acuminate, slightly incurved above the axil, very 

 entire at the margin." J. Ag. Sj). Alg. 2, p. 684. 



Hab. Greenland, Vahl, fide J. Agardh. 



7. Delesseria rostrata, J. Ag.; "frond subfiliforra, pinnato-dichotomous, the 

 upper segments patent, linear, acuminate, very entire at the margin ; conceptacles 

 immersed in the terminal segments, thrice as thick as the excurrent beak -like point 

 of the raraulus and shorter than it ; sori of tetraspores elongated below the sum- 

 mit of the segments." /. Ag. Sj). Alg. 2, p. 685. 



Hab. Greenland, Fabricius, Vahl., fide /. Agardh. 



Sob-genus 3. Hypoglossum, Kiitz. Frond undivided, ohlong or lanceolate, 

 proliferous from the midrib ; rose-red. 



8. Delesseria Hgpoglossum, Lamour. ; frond linear-lanceolate, tapering at each 

 end, repeatedly proliferous from the opaque, inarticulate midrib with leaflets of 

 similar form ; at length much branched. Harv. Phyc. Brit. t. 2. J. Ag. Sp. Alg. 2, 

 p. 693. Hypoglossum Woodwardi, Kiitz. Sp. Alg. 875. Var, /3. oval folium, J. Ag. 

 leaves oblong, obtuse or subobtuse, not attenuated. Var. y.JUiforme, Menegh.; leaves 

 exceedingly narrow, much attenuated at both ends. 



Hab. Shores of Carolina and Georgia. Charleston Harbour, the three varieties 

 common. Prof Gibbes, W.H. H. Anas tasia Island, Dr.Durlee. (v. v.) 



Frond originating in a simple, lanceolate leaf, which, in the American specimens 

 is seldom more than three or four inches long and a quarter inch wide. This leaf is 

 delicately membranaceous, and has a percurrent, slender, inarticulate midrib formed 

 of numerous, closely packed cylindrical cellules. As the plant developes, the midrib 

 throws out at both surfaces numei'ous similar leaves which in turn bear others ; and 

 thus by the repeated production of new series of leaves from the midrib of the 

 older, the plant at length becomes a leafy ball, very dense with crowded foliage. 

 The margin is entire and generally flat. The membrane is composed of polygonal 

 cells of which those next the midrib are nearly equal-sided hexagons, those next 

 them oblong, and those toward the margin gradually smaller and more cylindrical. 

 Conceptacles globose, on the midrib. Tetraspores in oblong or linear sori, disposed 

 in pairs at opposite sides of the midrib in the smaller leaves. Colour a brilliant car- 

 mine-lake. Substance delicately membranaceous. The plant quickly becomes 

 orange and decomposes in fresh water, and in drying closely adheres to paper. 



In var. 7. the leaves are frequently much arched, exceedingly narrow, and taper- 

 ing to a very slender point. This variety remarkably contrasts with var. /3. whose 



