92 



CHLOROPHYCEAE 



Codiaceae: Codiutn (fleece). Fig. 63. 



This is a widely distributed, non-calcareous genus with several 

 species living in the colder oceans. The erect and fleecy thallus, 

 which is anchored either by a basal disk or else by rhizoids, varies 

 greatly in form and appears as branched worm-Uke threads, flat 



B A C F 1 J 



Fig. 63. Codium. A, plant of C. tomentosum. B, C. fragile, utricles. C, C. to- 

 mentosum, single utricle with hairs. D, C. tomentosum, portion of thallus with 

 medulla and cortical utricles. E-G, stages in formation of constriction at base of 

 utricle. H, propagule of C isthmocladiim. I, C. toynentosum, female gametangium. 

 J, C. tomentosum, male gametangium. K, C. toT?ientosum, juvenile thread. 

 L, C. isthmocladuyn, utricle with propagule. (A, after Taylor; B, C, E-G, J, after 

 Tilden; D, H, K, L, after Fritsch; I, after Oltmanns.) 



cushions, or as large round balls. In C. tomentosum there is a 

 central medulla of narrow forked threads and a peripheral cortex of 

 club-shaped vesicles which are the swollen apices of the forked 

 threads. Deciduous hairs may develop on the vesicles and scars are 

 to be seen marking their point of attachment, whilst annular 

 thickenings occur at the base of each vesicle and at the bases of the 

 lateral branches, although a fine pore is left for intercommunication. 



