Poh/siphonia.] ALQJE RHODOSPERME^E. 205 



A. Main filaments inarticulate. 



1. P. fruticulosa, Grev. Shrubby Poly siphonia. Stems dif- 

 fuse, branched from the base ; branches divaricating, pinnato- 

 dichotomous, much divided, inarticulate, set in the lower part 

 with short, horizontal, multifid ramuli ; in the upper more or 

 less distinctly pinnate, with larger, similarly divided branchlets ; 

 axils rounded; articulations of the ramuli shorter than broad; 

 dissepiments opaque ; veins anastomosing. Hutchinsia Wul- 

 fenii, Jg. Sp. Alg. v. ii. p. 95.— Fucus frutic. Turn. Hist, 

 t. 227. E. Bot. t. 16S6. P. fruticulosa. Harv. in Hook. Br. 

 Ft. v. ii. p. 327. (in part.) 



Bantry bay ; Miss Hutchins. Black rocks, Portrush ; Mr. D. 

 Moore. In the British Flora I confounded the two following under 

 this species, and the " Miltown Malbay" station, given in that work, 

 belongs to P. thuyoides. The true P. fruticulosa is readily distin- 

 guished by its diffuse growth, different ramification, and by the hori- 

 zontal multifid ramuli which clothe the stems. 



2. P. thuyoides, Harv. MSS. Arbor- Vitee Polysiphonia. 

 Stems tufted, rising from creeping filaments, erect, terete ; be- 

 low simple, and set with short spine-like ramuli ; above, much 

 and fasciculately branched ; branches crowded round the apices, 

 very erect, bipinnate ; pinnae pinnato-multifid ; axils rounded ; 

 articulations of the ramuli shorter than broad; dissepiments 

 opaque ; veins anastomosing. P. fruticulosa, Harv. in Hook. 

 Br. Fl. I. c (in part.) 



Rocky shores. Very abundant at Miltown Malbay. Portrush bay ; 

 Mr. D. Moore. 3—4 inches high, dull brown. Capsules very rare. 

 Granules and antheridia very frequently produced. The habit of this 

 is very different from that of the preceding"; indeed, at first sight, it 

 might readily be mistaken for P. nigrescens, a plant of a totally dif- 

 ferent structure. I am not aware that it has been previously described. 



3. P. cristata, Harv. MSS. Crested Polysiphonia. Stem 

 erect, compressed, subsimple below, decomposite above; 

 branches erecto-patent, more or less regularly bipinnate (as is 

 also the stem to the base) ; lower pinnae very short, their pin- 

 nules simple and broadly subulate ; upper longer, with pinnato- 

 multifid pinnules ; axils all acute ; ramuli, as well as branches, 

 inarticulate, reticulated with veins. Fucus cristatus. — 7. Miss 

 Hutchins in Herb, (not of Turner.) 



Very rare. Bantry bay ; Ii'm Hutchins. If specimens, which I 

 possess through the kindness of Dr. Hooker, be correctly named, 

 (which I have no reason to doubt,) this is not the var. y. of Turner's 

 Fucus cristatus ( Rhodomenia cristata, Grev.) ; and, consequently, 

 not the Rytiphlcea complanata of Agardh. Indeed, if the genus 

 Rytiphlaa be characterized by a transversely striate frond, this has no 

 claims to admission into it. This species is alluded to in the British 

 Flora, under P. fruticulosa, as a beautiful variety of that species, 

 found at Whit sand bay by Mr. Walter Arnott. 



