28 University of California Publications in Botany [Vol. lo 



tions of modifications lead me to believe that these two species must 

 hybridize in this locality. 



Both species are synoicous and hence it would be very difficult to 

 carry out definite hybridizing experiments. 



Fucus edentatus De la Pyl. 



Plate 60, figure 1 



"F. fronde longa valida, linear! dichotoma, integerrima, nervo 

 percurrente plerumque vix tumido vel obsoleto; conceptaculis ter- 

 minalibus, planis, simplicibus; lineari-lanceolatis ; parum acutis, vulgo 

 geminatis aut basi connatis, fronde non latioribus. " 



De la Pylaie, Flor. Terre-Neuve, 1829, p. 84. 



Fronds usually narrow, more or less flaccid, regularly dichotomous, 

 olive green to olive brown or yellowish, usually very black on drying; 

 segments mostly decidedly linear, at times cuneate, midrib distinct, 

 percurrent, cryptostomata few or none, receptacles mostly narrow, 

 linear-lanceolate, acuminate, inflated or complanate. 



Growing in the middle and upper littoral belts. From Sitka, 

 Alaska, to Coos Bay, Oregon. 



For a discussion of this species major see page 10. 



Fucus edentatus f. hesperius f. nov. 



Plate 21 



Frondes arborescentes, 30-40 cm. altae, angustae, coriaceae, dicho- 

 tomae, obscure olivaceo-virides, in sicco atrae, stipite cylindrato; seg- 

 mentis strictis, linearibus, 5-10 mm. latis, apicibus truncatis et valde 

 expositis, prominentibus, costis percursis; cryptostomatibus nullis vel 

 summe infrequentibus, receptaculis plerumque complanatis vel partim 

 valde inflatis, 2-3-furcatis, linearibus, 3-4.5 cm. longis apicibus acutis ; 

 conceptaculis numerosis. 



Growing on rock ledges exposed to the action of the surf, in the 

 upper third of the littoral belt. Cape Arago, at the entrance to Coos 

 Bay, Oregon. 



Type, Gardner, no. 2653 (Herb. Univ. Calif., no. 201159), May, 

 1914. 



This form grew in abundance in company with F. furcatus f. 

 angustus. The two groups of plants were, however, in slightly different 

 altitudes in the belt, and were not indiscriminately intermixed. AVhen 

 the two sets of plants are dried, they are easily distinguishable by the 

 smoothness of the segments, forma hesperius being smooth and usually 

 shining, while forma angustus is rough, due to caecostomata, and is of 

 a duller color. 



