vol.i] Setehell— Gardner. — Alger of Northwestern America. 259 



The type of this form is Xo. 6S0 mentioned above. The plant 

 is near to the preceding form, but while that is a plant of the 

 exposed shores and consequently less ample, the present form is 

 a plant of the more quiet waters where the opportunities 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 bnllate. Xo. 683 is a shorter, less ample plant with a 

 distinctly cordate base with the mucilage ducts in the blade of 

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

 bullae very distinct. With the exception of the bullae it might 

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



Laminaria dentigera f. brevipes Setehell and Gardner f. 



nov. 



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

 tened above: otherwise similar to the next. 



Agattu Island, Alaska, Townsend, Xo. 5763!; Kyska Island, 

 Alaska, Townsend. Xo. 5771! 



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

 ure (1889. pi. 2. f. 10) in habit 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 above. 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 blade, the mucilage ducts are scanty, 

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

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



Laminaria dentigera f. longipes Setehell and Gardner f. 

 nov. 



Stipe 25-50 em. long, soou compressed, and above very 

 decidedly flattened. Otherwise simdar to the preceding. 



On stones in the lower literal and upper sublitoral zones. 

 Unga, Alaska, A.A.L., Xo. 5058!; Karluk, Kadiak Island, 

 Alaska. W.A.8., Xo. 5072! 



This form looks very much like L. digitata f . typica with the 

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



