128 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



fornia seems to show that we are dealing with a very widespread species, 

 and one which exhibits much variation in branching and habit in re- 

 sponse to different ecological conditions. 



The extreme variability in size, branching and shape of the inter- 

 genicula due to the wide tolerance of this species to great amplitudes of 

 temperature, salinity, gas-availability, exposure and agitation make it 

 difficult to give any single set of characteristics by which the species in 

 its many variations may be identified. Several names applicable to these 

 variants appear in the literature, however, and it seems desirable to use 

 some of them in an effort to separate, however artificially, some major 

 aspects of the variability. Four groups of variants may be recognized 

 under such varietal names. 



Corallina vancouveriensis var. vancouveriensis 



The variety which includes the type of the species is one in which the 

 tendency to verticillate branching is at a minimum, the lateral pinnae 

 usually long and simple, and the conceptacles long-pedicellate. Plants 

 agreeing closely with the type illustration of this variety do not seem to 

 occur in Mexico. 



Corallina vancouveriensis var. densa Yendo 



Yendo, 1902, p. 719, pi. 55, fig. 1, pi. 56, fig. 17. 



This variant is marked by denser, more compact form, mainly by a 

 moderate development of the verticillate tendency of the branching and 

 by a relative shortening of the segments. The lateral pinnae are mostly 

 simple. Such plants appear to take the place of the southern var. lyco- 

 podioides in the northern part of the range of this species. 



Corallina vancouveriensis var. aculeata (Yendo) comb. nov. 



Corallina aculeata Yendo, 1902, p. 720, pi. 55, fig. 3, pi. 56, figs. 

 18-19. 



Setchell and Gardner first recognized this as a variant of Yendo's 

 C. vancouveriensis but under a different combination. According to 

 Yendo's illustration, specimens placed here are those in which the 

 branching is confused, more or less verticillate, sometimes markedly so, 

 and particularly in which the pinnules tend to be pinnate or digitate 

 into several segments and (or) at least in part irregularly shaped, lobed 

 or digitate. Such plants occur occasionally within the range of var. 

 lycopodioides. 



