4 MINNESOTA BOTANICAL STUDIES. 



otherwise ordinary proliferations and so are surmounted by 

 spatulate or ovate-cuneate or branched leaf-like blades unless 

 these be broken. The blades of these vesicle-bearing prolifera- 

 tions are often branched when those of neighboring prolifera- 

 tions are of the common form. The vesicles when fully grown 

 are obovoidal or ellipsoidal, mostly 2.5 to 3.5 cm. in length. In 

 the older parts of the rachis, as first described by Ruprecht, 

 they are more bulged out, becoming nearly spherical and hence 

 somewhat shorter. In the old vesicles the surmounting blade 

 has always disappeared. 



Comparison with other Laminariaceae. 



The morphology of the plant was not understood by early 

 writers because of the fragmentary material studied. Turner and 

 Agardh seem to have had only small portions of the stipe with 

 no part of the lamina. Ruprecht apparently had good material. 

 His Plate IV. is accurately drawn and shows both rachis and 

 lamina. He, however, overlooked the branched laciniate pro- 

 liferations ; at any rate he does not show them in the drawing. 

 Areschoug and De Toni seem to have neglected the work of 

 Ruprecht. They do not mention the laminae of the branches 

 and so fail to show tfye morphological similarity of this plant 

 with other Laminariaceae. Professor Setchell 9 first pointed out 

 the fact that Egregia conforms to the Alaria type in its morphol- 

 ogy. It should be noted, however, that the plant body of 

 Egregia shows a much higher degree of differentiation in the 

 branching of the stipe and the character of the proliferations. 

 In Alaria the proliferations occur only on the stipe. They are 

 known as gonidiophylls. In Egregia only one kind of prolifer- 

 ations, the short somewhat cuneate form, bears gonidia. The 

 others, both of the rachis and lamina, are sterile and should not 

 be spoken of as gonidiophylls. 



Egregia consists, as the other Laminariaceae do, of holdfast, 

 stipe and lamina, but the branching of the stipe gives rise to 

 members (branches) each having the general characteristics of 

 the entire frond in Alaria. The multiform proliferations largely 

 replace functionally the lamina, which is here greatly reduced 

 in size and importance. Because of the great elongation of the 

 stipe a floating apparatus has become necessary and this is pro- 

 vided in the vesicles developed by the swelling of the stalks of 

 certain proliferations. 



