198 University of California Publications in Botany [Vol. 8 



Amer., 1903, p. 221 (in part). " Ilormiscia Worniskjoldii'' Collius, 

 Green Alg. N. A., 1909, p. 368 (in part). "Urospora Warmskjoldii f. 

 vancoKvcriana" Tilden, Amer. Alg. (Exsicc), no. 381. 



The plants distributed in Tilden 's American Algae under no. 381 

 are by far the most robust of any of the genus Hormiscia yet seen. 

 In several characters they resemble //. Worniskioldii closely, but differ 

 decidedly in diameter and in the character of the ehromatophore. 

 The maximum diameter of the fertile segment is 3 mm. or even more. 

 The ehromatophore seems to be a close, very little, if at all, perforate 

 ring. From //. sphaerulifera, H. vancouveriana differs both in its 

 greater thickness and in the proportionally longer fertile cells. 



Hormiscia v-ancouverimia is known only from the type locality 

 and, as far as we are aware, from a single collecting. It is to be 

 hoped that it may be rediscovered and studied in the living condition. 



12. Chaetomorpha Kuetz. 



Filaments composed of a single unbranched series of multinucleate 

 segments, all except, usually, a few long basal segments capable of 

 division and reproduction, attached by more or less branched, shorter 

 or longer rhizoids, often coalescing, always attached at first, later some- 

 times loosening and continuing in a free state ; membrane of segments 

 thick, firm, usually distinctly lamellate in age ; ehromatophore a 

 parietal band, more or less perforate (or in age broken into small 

 disks), with numerous pyrenoids; reproduction by 4-ciliated zoospores 

 produced in little changed segments, and by 2-ciliated isogametes ; 

 thick-walled akinetes fonned from single segments; mostly marine 

 species. 



Kuetzing, Phyc. Germ., 1845, p. 203. 



The genus Chaetomorpha was founded by Kuetzing in 1845 (May), 

 as indicated above, with fifteen species referred to it, all of which still 

 seem to be closely generically related. It preceded by only two months 

 (cf. Harvey, 1858, p. 84) the publication of Hassall's Aplonema (1845, 

 p. 213, July). It seems to be generally recognized as a genus and 

 to be retained in spite of the fact that it approaches Ehizoclonium 

 on the one side and Hormiscia on the other. From Rhizoclonium 

 species in typical form it is readily to be distinguished by the lack 

 of branches of any kind, rhizoidal or otherwise. Some species of 

 Ehizoclonium, however, lack all branches and consequently resemble 

 closely the unattached and expanded species or forms of Chaetomorpha. 



