ECOLOGY AND TAXONOMY OF HaUmeda 



41 



multi-holdfast systems: the "rope-like extensions" of micronesiva, and 

 a system of adventitious attachment found in spreading and cushion 

 life-forms. 



Fig. 19. H. opuntia, festooning Acropora sp. on the reefs of the Similan Islands, eastern 

 Indian Ocean. The spreading thallus is anchored at several places, and the older 

 parts of the thallus (shown near the centre) die away and become sejaarated from the 

 younger portions, producing a clone of several younger thalli. The multi-holdfast 

 system is a useful growth strategy- for a clone that may be grazed. Long dimension 

 of the clump in right-centre is approximately 7 cm. 



"Rope-like extensions" were described by Hillis (1959) for 

 micronesica. Fine rhizoidal-type filaments extend from several apical 

 segments and become intertwined into ropes which attach to the 

 substrate. Halimeda micronesica plants may be held down bj^ an 

 orange-brown mat of these ropes which may be up to 6 cm or more in 

 length. 



