48 University of California Publications in Botany [Vol. 10 



it at Sitka in June, 1910, when it was in full fruit, and at Friday 

 Harbor in July of the same year. The type and the two cotype speci- 

 mens have all of the receptacles complanate, and are apparently 

 immature (plate 49), but in the other collections mentioned many of 

 the receptacles are much inflated (plate 50). The species is one quite 

 free from mucilage as compared with other species of Fucus growing 

 in the same localities but much lower down in the littoral belt. It 

 seems to have become fixed as a form, and has the distinct habit, or 

 character, of being able to persist in the upper two feet of the littoral 

 belt, in which habitat it is necessarily uncovered the greater part of 

 the twenty-four hours each day. It inhabits rock ledges, either steep 

 or sloping, yet it is strictly confined to the upper, very narrow, belt. 

 Its fronds are lighter and somewhat more fibrous than those of any 

 other form. 



Fucus evanescens f. magnificus f. nov. 



Plates 51 and 52 



Frondes foliaceae, 20-30 cm. altae, subcoriaceae, dichotomae, vel 

 partim secundae, inferne obscure brunneae, superne luteolae, siccatae 

 olivaceo-brunneae ; segmentis comparative brevibus, linearibus vel 

 cuneatis, plus minus contortis, 2.5-3.5 cm. latis, costa superne pallidum 

 evanida, cryptostomatibus variis usque ad 50 in quoquo cm. quadrato, 

 vulgo paraphysum cristis exsertis quando juvenibus conspicuis ; recep- 

 taculis distincte definitis, valde tumidis, mucosis, integris vel decom- 

 posite furcatis, truncatis vel aeutis, latitudine et longitudine valde 

 variis, vulgo flavis; eonceptaculis numerosis valde conspicuis. 



Growing in great profusion in the middle and upper littoral regions. 

 Juneau, Alaska, to Puget Sound, Washington. 



Type, Gardner, no. 2337 (Herb. Univ. Calif., no. 205690), Griffin 

 Bay, San Juan Island. Washington, July, 1910. 



So far as my observations extend, this form seems to be the most 

 abundant of all the forms included in the above mentioned region. 

 It varies quite widely in the shape of the receptacles as shown in 

 plate 51. Some receptacles are simple, others decompositely furcate, 

 many quite obtuse, others decidedly acute, but all are definitely 

 delimited and swollen almost to the bursting point with mucilaginous 

 substance. The segments are wide and foliaceous, not narrowing at 

 the forkings, and the tendency to the strict habit of growth often 

 makes them quite contorted. 



One of the distinguishing characters is the sparsity of receptacles 

 maturing at any one time. This habit, marked in only a few of our 

 forms, should receive more study in the field. My opinion is that the 



