612 University of California Publications in Botany [Vol. 8 



We have made no attempt to correlate anatomical differences with 

 the gross morphological characters of the various forms of the genus 

 which we have studied. Such studies as we have made of a rather 

 extensive array of material from different habitats and localities, 

 have all been confined to the general shape and size of the plant as a 

 whole, and in this we have found a great range of variation. As to the 

 hapteres, Fucus costatus Turner is said to have numerous, slender, 

 unbranched hapteres. We have come across no forms except those 

 in the juvenile stage that have this character. Ours are all many 

 times dichotomously branched in unmutilated specimens. The thick- 

 ness of the hapteres seems to depend upon the habitat. Those growing 

 in quiet waters are usually longer and more slender than those growing 

 in exposed situations. Regarding the stipe, it is to be noted that there 

 are extreme variations. In Turner's description, the stipe is only an 

 inch long and ''of the size of a crow's quill." On two occasions, 

 seven years apart, one of us (Gardner) has studied colonies of living 

 plants growing in quiet water at Oak Bay, Victoria, British Columbia, 

 and at Roche Harbor, San Juan Island, Washington, whose rigid 

 stipes were up to six and a half decimeters long and ten centimeters 

 wide at the flattened top. In all cases, they are covered with finer 

 or coarser longitudinal grooves. Between these two extremes there are 

 innumerable gradations in length and thickness. The blades, as we 

 have studied them, range in width from about five to seven centimeters 

 in C. Turneri var. pertiisa (cf. Collins, Holden and Setchell, lac. dt., 

 no. XXXIV) to forms mentioned above at Oak Bay and Roche Harbor, 

 with blades up to sixty-five centimeters wide and only one to two times 

 as long. Some of the forms of medium width, growing in the Puget 

 Sound region, are up to three meters long. The bullations are finer 

 or coarser, deeper or shallower, but not in any way correlated with 

 other characters. The bases are narrowly to broadly cuneate, passing 

 over into slightly cordate and finally auriculate-cordate. The con- 

 sistency of the blade seems to be correlated with the exposure. They 

 are more or less thick and rigid in the locations exposed to the heaviest 

 surf, and thinner and flabby in quiet water. With our present knowl- 

 edge, we do not feel able to recognize more than one exceedingly 

 variable species, and we are not able even to state the limits of forms. 



