Alga.] CALIFORNIA. 165 



2. Ptilota pectinata. Harv. MSS.; jugamento compresso filiformi subbipinnato, pinnis 

 pinnulisque alternis, ramulis extremis (nascentibus pectiniformibus) distichis divaricato- 

 multifidis. 



This, too, in its young state, is distinguished like the last hy a very beautiful character, a little comb-like 

 ramulus, inciso-serrate on its lower side, being placed opposite the insertion of each pinnule j but in older 

 fronds, from a frequent multiplication of this structure, nothing is -visible but a confused fascicle of multifid 

 ramuli. The pinnules, or secondary branches, are closely set with similar ramuli, alternating with each 

 other, and in the spaces between these are situated fructiferous multifid ramuli, which bear dense clusters 

 of trisporous capsules. 



Trib. IV. Gastrocarpeje. 



1. Iridasa papillata. Grev Sphasrococcus papillatus. Ag. 222. 



A fine species, and an undoubted Iridaa. Shape of I. edulis, thick, flexile, its upper half bearing elon- 

 gated papillae in great abundance, each of which terminates in one or more umbilicated warts. These warts 

 contain a mass of small seeds, lodged in a central cavity, and differ principally from regular capsules, (such 

 as are found in the Floridea,) by passing into the pediceles, and thence into the frond, without any percep- 

 table alteration in the size or shape of the subjacent cellules. The outer coating of the frond also is continued 

 round them without interruption, and the whole is perfectly opaque. 



Trib. V. Siphoned. 



1. Codium tomentosum. Stackh. — Fucus tomentosus. Turn. t. 135. 

 Trib. VI. Ceramie^e. 



1. Ceramium obsoletum. Ag. Sp. Alg. 2. p. 145. 



Parasitical on Iridea papillata. 



1. Polysipbonia verticillata. Harv. MSS.; filis nanis repentibus parce ramosis; ramis 

 obsolete articulatis, ramulis subverticillatis simplicibus acutis incurvis multistriatis articulis 

 diametro brevioribus. 



A very curious and distinct little species, 1-2 inches high, with a good deal the habit of Cladostephus, 

 but possessing the structure and substance of Polysiphonia. Colour a deep brown. 



