1925] SetcheU-Gardner: Melanophyceae 631 



Leman (lac. cit.) was the first to publish a critical diagnosis of 

 the species under the combination, Laminaria porra. Nothing was 

 done with it in a botanical way until 1876, when Areschoug redescribed 

 it from material collected by Dr. G. Eisen, at Santa Catalina, Cali- 

 fornia, placing it with Nereocystis as N. gigantea. Later (1881) he 

 created the genus Pehigophycus to receive the same species where it 

 remained until the combination employed here was made (cf. Setchell, 

 loc. cit.). 



tribe 3. LESSONIOPSEAE setchell 



Members of the Lessoniaceae having specialized sporophylls arising 

 as outgrowths on the outer margins of the transition place where 

 splitting is about to occur. 



Setchell, Kelps of the U. S. and Alaska, 1912a, p. 160. 



The tribe of the Lessoniopseae might perhaps be placed with equal 

 propriety either under Lessoniaceae or under Alariaceae, since the 

 sole genus, monotypic, has the characters of each of these families. 

 The plant, however, has the habit of a Lessonia and this influences us 

 strongly to place it nearer to Lessonia than to Alaria. 



54. Lessoniopsis Reinke 



Frond differentiated into holdfast, stipe, blade, and sporophylls; 

 holdfast consists of a dense mass of short, thick, dichotomously 

 branched hapteres; stipe short, cartilaginous, very dense and rigid, 

 arborescent, more or less deeply furrowed, merging into hapteres below, 

 irregular in outline, profusely dichotomously branched above, branch- 

 ing taking place by splitting in the meristematic region, terminating 

 in long narrowly linear blades with distinct percurrent midrib and 

 stipitate base ; the meristematic transition region at the base of each 

 blade giving rise to sporophylls in pairs, 1-3 pairs each season. 



Reinke, Studien zur Entwick. Lam., 1903, pp. 25-28. 



Lessoniopsis is one of the many monotypic genera of kelps thus 

 far known exclusively on the west coast of North America. It was 

 established by Reinke to receive Lessonia Hit oralis Farlow and 

 Setchell. Although among the relatively recent discoveries, its morph- 

 ology, anatomy and life-history, except as to the embryonal stages, 

 have been quite thoroughly made known. 



In its method of development of the sporophylls, its affinities are 

 close to Pterygoplwra. It resembles Lessonia in its method of dicho- 

 tomous branching of the blade and the consequent production of new 

 blades. 



