HOW TO KNOW THE SEAWEEDS 



13a Thollus fQaments without cross walls, ending at the surface in a 



continuous layer of inflated utricles. Fig. 24 Codium 



Fig. 24. Codium iiagile (Suringar) Harlot 



A small group of utricles showing their 

 origin from the non-septate, branched fila- 

 ments making up the thallus. X 50. In 

 this species the utricles are pointed, but 

 in other species they are smooth. Several 

 kinds of Codium occur along the Pacific 

 Coast and along the Atlantic Coast from 

 North Carohna southward. The common- 

 est Atlantic species, C. dichofomum (Hud- 

 son) S. F. Gray and the common Pacific 

 one, C. fragile, are both erect, dichotom- 

 ously branched, cylindrical plants. Other 

 species are flattened at the points of 

 branching while still others are prostrate 

 and somewhat cushion-shaped or with 

 lobe-like branches. 



Figure 24 



13b Thallus filaments with cross walls; surface without inflated utricles 

 14 



14a Brownish in color; axis with a solid medulla of compacted, 

 branched, longitudinal filaments 15 



14b Reddish in color; medullary region not solid, the thallus filaments 

 nowhere compacted 1° 



15a Thallus gelatinous; branching irregular; ultimate branches often 

 short. Fig. 25 Eudesme virescens 







Fig. 25. Eudesme virescens (Carmichael) 

 J. Agardh 



A small upper portion of a plant to show 

 the irregular short branches and the com- 

 pacted medulla which shows through the 

 looser, more gelatinous cortical region as 

 a denser core, X 1.5. This species is found 

 widely along the Atlantic Coast. It is the 

 only member of the genus in our flora. A 

 slender form commonly grows on the 

 leaves of Zostera. 



Figure 25 



34 



