APPENDIX. 



like the teeth of a comb. And this is the case with the pretty form IE. tesselatus, 

 first discovered by the Rev. F. W. Hayden, in rock crevices on tlie rugged surface 

 of Filey Bridge, at the further extremity. And as this secund branchleting occurs 

 on both alternately- and o^^'^o^iiQlj -Iran died specimens, it would seem that these 

 varieties of habit are of little importance. 



The oppositely-branched is commonest on the south coast, and the alternate, or 

 alternato-opposite, in the north. But they are found conversely. Dr. Cocks fur- 

 nished fine alternato-secund to his AJgarum Fasciculi from Plymouth; and qpposito- 

 secund, with occasional double pairs, was gathered off a buoy at "Whitby this year 

 (1862). Filey Bridge affords the three varieties. 



The peculiarities of E. tesselatus appear to be the secund branchlets; a beautiful 

 green-oiivQ colour, and a richness and closeness of branching quite unknown in the 

 larger forms, which often become straggling and have long portions of their stems 

 naked. In a collection it will be well to call this plant JEctocarpus granulosus^ 

 var. seeimdatiis — a name bestowed upon one of the secund forms by Lyngbye; and 

 as Agardh unites under E. granulosus the oppositely-branched Icetus, the collector 

 may, if he pleases, subdivide the three forms by separate titles. The epithet tesselatus 

 is equally applicable to all, for it was suggested by the tesselated appearance of the 

 fruit; but this can only be observed under a very good microscope. The Whitby 

 specimens, before alluded to, were furnished, besides the usual fruit, with globular 

 bodies, having the appearance of spores inclosed in a hyaline cell. These were seated 

 for the most part on the stems, the tesselated fruit on the branchlets. It is ad- 

 mitted by all, that the fructification of the Ectocarpi is very imperfectly understood; 

 the tesselated formations not having the usual characters of spores. 



EED GKOUP. 

 Family YII. EHODOMELACE^. 



EYTIPHL^A OXYACANTHA. 



A most delicate and lovely form discovered by Miss Turner in Jersey, in 1855, 

 and provisionally called jS. oxi/acantlm by Dr. Harvey. He is unwilling, however, 

 to subdivide species unnecessarily, and has satisfied himself that this attractive little 

 plant is but a slender and graceful variety of Hytiplilcea tlimjoides (fig. 101.) Its 

 general appearance is much less stiff and formal than that of the usual tJiuy- 

 oides, for the branchlets, instead of being short, and re-bran chleted with another set 

 shorter still, are longer and simpler, being rarely re-bran chleted at all. It seems 

 hard not to allow so interesting a variety a special name, but almost as much 

 difference may be observed in the stiff'er or slenderer forms of Poli/siphonia parasitica 

 as between B. oxyacantlia and the coarser It. tliuyoides. 



POLTSIPHOmA FCETIDISSIMA. 



Specimens under this name having been distributed in Dr. Codes' Algarum 

 Fasciculi, it is necesssry to mention that Dr. Harvey does not consider it specifically 

 distinct from P. jibrata (fig. 113). It is rather purpler in hue; but whether this 

 arises from anything more than its growing on mud in a harbour, where the water 

 cannot be so pure as on a more open sea, seems doubtful. Its professed halitats are 

 the landing-places on the shore of Mount Edgcumbe, and Torpoint. 



90 



