1 88 



PHAEOPHYCEAE 



less woody, being by far the stoutest known among the algae. The 

 numerous Hnear laminae, about forty in number, are borne 

 terminally, and though they have no distinct mid-rib nevertheless 

 the central portion is much thickened. Long sporophylls are also 

 produced laterally on both sides of the stipe near the transition area. 

 These fronds, which possess continual growth, appear first in 

 February and fruit in the following September or October, the 



Fig. 127. Eisenia. A, young sporophyte of £". bicyclis. B-F, stages in develop- 

 ment of the adult sporophyte of E. arborea. G, base of an adult plant of 

 E. bicyclis. H, mature sporophyte of E. bicyclis. (After Tilden.) 



sporangia and paraphyses being borne in sori on both sides of the 

 sporophylls and also on the terminal laminae. Pterygophora is a 

 monotypic genus found from Vancouver Island to Lower Cali- 

 fornia where it grows characteristically at the bottom of deep 

 chasms possessing 12-15 ft. of water at low tide. It has been 

 estimated that individual plants may live for as long as 13 years. 



