HOW TO KNOW THE SEAWEEDS 



66b Rhizoids produced from several cells near the base. Fig. 98 



Uiospora 



Fig. 98. Urospoia penicilliformis 

 (Roth) Areschoug 



A. The basal part of a plant to 

 show the rhizoids arising from 

 several lower cells, X 220. B., C. 

 Two stages in the production of 

 zoospores in older parts of fila- 

 ments, X 300. This is perhaps 

 the commonest of several species 

 occurring in New England and 

 along the Pacific Coast from cen- 

 tral California northward. They 

 grow on rocks or woodwork as 

 fine, green, silky tufts up to 10 

 cm. long or more. 



Figure 98 



67a Filaments 70 ^ or less in diameter, unbranched, or with a few 

 short lateral branches. Fig. 99 Rhizocionium 



DI 



1 



Figure 99 



Fig. 99. Rhizocionium kerneri Stockmayer 



A small part of a filament to show the diameter and cell shape, 

 X 235. This is one of several species which may be found widely 

 along any of our coasts. 



77 



