1920] Setchell-Gardncr : Chlorophyceae 191 



0.5 mm. to. 3 mm. in diameter. To thi.s section we are inclined to refer 

 H. Wormskioldii (Mert.) Fries, H. sphaeruUfera S. and G., and H. 

 vancouveriana (Tilden) S. and G. 



Key to the Species 



1. Rhizoids extramatrical; zoosporangia not over 200m in maximum diameter 2 



1. Rhizoids largely or entirely intramatrical; zoosporangia 200m or over in maximum 



diameter 3 



2. Zoosporangia not over 100m in maximum diameter 



1. H. penicilliformis (p. 191) 



2. Zoosporangia over 100m in maximum diameter 2. H. doliifera (p. 193) 



3. Zoosporangia below 300m in maxiniuni diameter 4 



3. Zoosporangia above 500m in maximum diameter 5 



4. Zoosporangia oblong-cylindrical, up to 175m, or even 200m, diameter 



4. H. grandis (p. 195) 



4. Zoosporangia short, barrel-shaped, up to 225m diameter 



3. H. tetraciliata (p. 193) 



5. Chromatophore solid or inconspicuously perforate 6 



5. Chromatophore coarsely reticulate 6. H. Wormskioldii (p. 196) 



6. Zoosporangia nearly globular, up .to 700m diameter 



5. H. sphaeruUfera (p. 196) 



0. Zoosporangia globular to ventricose-ellipsoidal, 1 mm. to 3 mm. maximum 

 diameter 7. H. vancouveriana (p. 197) 



1. Hormiscia penicilliformis (Roth) Fries 

 Plate 9, fig. 4 



Filaments dark green, attached by extramatrical rhizoids from a 

 few of the lower segments, 30-60ju, up to 90/^ diam., 0.3-2.5 times as 

 long as the diameter; vegetative segments mostly cylindrical, fertile 

 more or less swollen to liarrel-shaped ; chromatophore usually dense, 

 a continuous parietal banc], or at times somewhat fenestrate, pyrenoids 

 relatively few and large. 



Growing on rocks and timbers exposed to the surf. Alaska (Port 

 Clarence, etc.) to central California, 



Fries, Flora Scanica, 1835, p. 327 ; Collins, Green Alg. N. A., 1909, 

 p. 368. Conferva penicilliformis Roth, Cat. Bot., Ill, 1806, p. 272. 

 Urospora penicilliformis Setchell and Gardner, Alg. N.W. Amer., 

 1903, p. 220 (in part). Urospora incrassata Setchell and Gardner, 

 Alg. N.W. Amer., 1903, p. 221 and of Collins, Holden and Setchell, 

 Phyc. Bor.-Amer. (Exsicc), no. 1125 (not of Kjellman). Hormiscia 

 incrassata Collins, Green Alg. N. A., 1909, p. 369 (excl. syn. of Kjell- 

 man). 



The exact nature of the Conferva penicilliformis Roth is a subject 

 of doubt, and no one has published any statement either as to the 



