94 
L AMIN ARI ACEiE. — Laminaria . 
IV. 
Hab. Floating near Narragansett Pier, XL I. Mr. Olney. (v. s.) 
I introduce this undescribed and scarcely known plant, because it has already 
obtained publicity in Mr. Olney’s list of Rhode Island plants, quoted above ; but I 
am unable to give a satisfactory description from the few fragments that have 
reached me ; and probably, after all, these may belong to some strangely anomalous 
form of L. saccliarina. The fragments sent me by Mr. Olney and Professor Bailey 
are labelled as part of a large Alga resembling L. saccliarina in appearance, but 
having a trilaminate frond ; that is, from the centre of the lamina, along its 
whole (?) length, there projects a wing or additional lamina, making, with the two 
halves of the true leaf, a third lamina. Nothing is known of the stipes. 
7. Laminaria digitata, Lam. ; stem robust, woody, terete below, compressed above, 
expanding into a leathery, oblong, or ovate frond, which is deeply cleft into many 
linear segments of irregular breadth. J. Ag. Sp. Alg. vol. 1, p. 134. Harv. Pliyc. 
Brit. t. 223, and t. 338. Hafgygia digitata, Kiitz. Sp. Alg. p. 577. Phyc. Gen. 
t. 30, 31. Fucus digitatus , L. Turn. Hist. t. 162. E. Bot. t. 2274. 
Hab. On rocks, at and below low-water mark. Common as far south as Cape 
Cod. Narragansett Pier, R. I., Mr. Olney. (floating only), (v. v.) 
Root formed of many stout branching holdfasts united together in a conical 
mass. Stipe from two to six feet long, cylindrical below, from a quarter inch to an 
inch in diameter at base, solid, tapering, and becoming compressed upwards, and 
terminating in the base of a standard-like broad lamina. Lamina from one to five 
feet long, or more, from one to three feet wide, deeply cleft from the apex to near 
the base into many linear strap-shaped segments of uncertain breadth. Substance 
of the stem woody, but flexible, horny when dry ; of the lamina leathery. Colour 
olive, becoming dark in age. 
Possibly more than one species is here confounded. Some varieties, like that 
figured in Pliyc. Brit. t. 338, are very narrow, 'with very much compressed, or even 
flattened stipes, and of a dark blackish-brown colour and glossy surface. Others, 
which I have from Boston Bay, have dried extremely pale, and though I have not 
seen perfect specimens of these, I remember to have noticed on the beach near 
Nahant some forms of pale colour and with very flat stems, which may belong to 
a peculiar species. The limits of species among these gigantic Algse can rarely be 
determined from Herbarium specimens alone, and should be fixed by persons 
familiar with the plants in their places of growth, and who have watched the 
development of the frond through all its stages. 
