v; CRYPTONEMIACE^. 179 



net-work ; the cortical of moniliform, vertical, dichotomous filaments, set in a firm 

 gelatine. Sporiferous nucleus immersed in the substance of the frond, roundish, en- 

 closed in a saccate placenta (?) formed of closely interwoven filaments, consisting 

 of many confluent nucleoli or masses of minute spores. Tetraspores collected into 

 dense sori lodged beneath the superficial cells, roundish, cruciate. 



Technically this genus can only be distinguished from Gigartina by having its 

 nuclei immersed in the inner substance of the frond, and not contained in external 

 tubercles or conceptacles. The structure of the frond is similar in both genera, but 

 the Jridccce have generally simpler, less regularly cleft, and more widely expanded 

 laminaj, of a brighter colour and more glossy surface. Their substance is soft, be- 

 tween fleshy and membranous when fresh, somewhat cartilaginous when dry, soon 

 dissolving into gelatine if again moistened after having been once dried. Many 

 species have been described, but I fear often on insuflicient data, and I regret that 

 the materials at my command are insufficient to enable me to say, whether all or 

 how many of the following sj)ecies ought to be retained. 



1. Irid^ea jninor, J. Ag. ; " frond ovate oblong, sub-simple, smooth, abruptly 

 attenuated into an evident, fiattish stipes." J. Ag. Sp. Alg. %p. 252. 



Hab. California, Douglas. 



" Fronds gregarious, 2 — 3 inches high, an inch liroad, rising with an elongated 

 fiattish stipes nearly an inch long, then abruptly cuneately expanded into an ovate 

 or oblong, entire lamina, wliich is either smooth or verrucated Avith sub-prominent 

 conceptacles ; rounded and very obtuse at the apex. Colour livid, brownish. 

 Substance gelatinous, cartilaginous when dry." /. Ag. 



2. iKiDiEA laminarioides, Bory ; frond stipitate, linear- obovate or sub-lanceolate, 

 simple or cloven into numerous narrow obovate or lanceolate lacinife ; nuclei 

 densely scattered, sub-prominent. J. Ag. Sp. Alg. 2, p. 253. Kutz. Sp. Alg. p. 

 726. 



Hab. Russian America, Postcls aiul Ritprecht. California, Douglas ! Coulter ! 

 (v s. in Herb. T. C. D.) 



Stipes one to two inches long, cylindrical at the base, soon cuneate and com- 

 pressed, gradually widening to half an inch, and then suddenly expanding into the 

 base of a narrow, obovate or oblong, linear frond, one to two feet long, obiuse, or more 

 or less acute or acuminate at the apex. Sometimes the frond divides a little above 

 the apex of the stipes into numerous frondlets ; but this chiefly takes place in spe- 



A A 2 



