Vol.1] ISetchell- Gardner. — Algw of Xorihirestern America. 259 



The type of this form is No. 680 mentioned above. The plant 

 is near to the preceding form, hut while that is a i)lant of the 

 exposed shores and conseqnently less ample, the present form is 

 a plant of the more quiet waters where the op])ortunities are 

 given to increase in width with the result that some of the plants 

 are certainly gigantic for this species. In older plants the whole 

 surface is bullate. No. 683 is a shorter, less ample plant with a 

 distinctly cordate base with the mucilage ducts in the ])lade of 

 moderate size and close under the surface, but with the marginal 

 bulla? very distinct. With the exception of the Inillre it might 

 pass very well for a specimen of L. afrofiilra J. Agardh. 



Laminaria dentigera f. brevipes Setchell and (larduer f. 



no v. 



Stipe 10-15 cm. long, nearly cylindrical but somewhat flat- 

 tened above; otherwise similar to the next. 



Agattu Island, Alaska, Townsend, No. 5768! ; Kyska Island, 

 Alaska, Townsend, No. 5771! 



The form described here agrees fairly well with Kjellman's fig- 

 ure (1889, pi. 2, f. 10) in hahit and is fairly distinct from the fol- 

 lowing form which, however, seems also to belong under Kjellman ' s 

 species. The stipe in f. brevipes is short and stout as compared 

 with f. longipes, and not so noticeably compressed a])ove. The 

 whole plant seems thicker and denser. The mucilage ducts are 

 present in the stipe in a dense circle just under the surface 

 tissues, are elongated radially, and have clumps of secreting cells 

 at the inner end. In the l)lad(% the mucilage ducts are scanty, 

 in fact we supposed at first that there were none present, Imt 

 they are present and answer well to Kjellman's description. 



Laminaria dentigera f. longipes Setchell and Gardner f. 



no v. 



Stipe 25-50 cm. long, soon compressed, and al)ove very 

 decidedly flattened. Otherwise similar to the preceding. 



On stones in the lower litoral and upper sublitoral zones. 

 Unga, Alaska, A.A.L., No. 5058!; Karluk, Kadiak Island, 

 Alaska, ir.A.N., No. 5072! 



This form looks very much like L. digifafa f . fi/pira with the 

 cuneate base. The mucilage ducts in ^e stipe, however, distin- 



