86 MARINE ALG^B 



ing a dot or spore-cluster, occur at intervals on the margin ; plant six to 

 eight inches long; thin and silky in texture. Abundant on the Cali- 

 fornia coast. (Plate XXIII.) 



N. Suprechteanum. Frond one foot to two feet long, spreading 

 from narrow base and dividing by forking into deep-cut, broad, strap- 

 like lobes; top divisions rounded ; traversed lengthwise by parallel veins $ 

 margin of the older parts bordered with a narrow frill of thin ruffled 

 membrane which sometimes extends also over parts of the surface of the 

 frond ; substance somewhat rigid : color dark red to purple. It is found 

 on the California coast. (Plate XXIV.) 



N. punctatum. Frond six to twenty inches long and of the same 

 width, dividing in a forking manner ; crowded at top ; when in fruit, 

 covered with dark dots ; substance thin and silky ; color rose-pink. It 

 is found on the California coast. (Plate XXIV.) 



GENUS Grinnellia 



(Named for Mr. Henry Orinnell of New York) 



O. Americana. Frond a delicate membrane, rose-red or purplish 

 in color, leaf -shaped, four to eight inches long, one inch to four inches 

 wide, tapering at both ends ; margin entire, but much waved ; a line of 

 darker color through the center resembles a midrib ; masses of spores 

 form dots or specks irregularly over the whole surface ; grows from 

 a disk and short slender stem in bunches on shells and stones in deep 

 water. It is found washed ashore from Cape Cod southward, and is 

 luxuriant in New York Bay, where it can be found at any season, but is 

 in perfection in August. (Plate XXIV.) 



GENUS Delesseria 



D. sinuosa. Delicate, leaf -like membrane, with midrib and veins, 

 much indented and resembling in general outline an oak-leaf ; four to 

 eight inches long, two to four inches broad ; short stem ; color dark red, 

 often flecked with green. It grows in bunches in deep water, and is 

 easily distinguished, since it is the only alga having a midrib and veins, 

 and resembling the leaf of a tree. It is found washed ashore from Cape 

 Cod northward. (Plate XXIV.) 



J>. alata ("winged"). Frond rises from short stem, which flattens 

 and divides irregularly into many branches and appears like a midrib, 

 all bordered with narrow membrane one eighth of an inch to one inch 

 wide ; frond two to four inches long ; color light red or pink. It is 

 found on the shore from Cape Cod northward. (Plate XXV.) 



D. Leprieurii. Frond one inch to two inches long, very narrow, 

 with delicate midrib, forked, constricted at intervals ; branches start 

 from constricted points ; thin and delicate ; color purple. It is found 

 in tidal rivers near New York, and is common on the southern coast. 

 (Plate XXV.) 



SUBORDER BHODOMELEJE 



The genera included in this suborder are easily distinguished 

 when in fruit by the spore-cases, or cystocarps, which appear 



