2 L. HILLIS-COLINVAUX 



VII. Reproduction . . . . . . . . . . . . . . . . . . 197 



A. Sexual iDi-ocesses in Halitneda . . . . . . . . . . . . 202 



B. Vegetative reproduction of ilfa^JmecZa . . .. .. .. .. 212 



C. Reproduction in other Caulerpales . . . . . . . . . . 215 



D. Reproductive sti-ategy and the strawberry-coral model . . . . 221 

 VIII. Biogeography and Phylogeny . . . . . . . . . . . . . . 225 



A. Present distribution . . . . . . . . . . . . . . 226 



B. Palaeobiogeography and prehistory . . . . . . . . . . 232 



C. Rates of speciation within the genus . . . . . . . . . . 234 



D. A biogeographical approach to the phylogeny of the Caulerpales . . 237 

 IX. Productivity 241 



A. Production of organic carbon . . . . . . . . . . . . 245 



B. Carbonate production . . . . . . . . . . . . . . 253 



X. Haliineda Distribution in two Reef Systems . . . . . . . . . . 277 



A. The Glory Be reef, Ocho Rios, Jamaica . . . . . . . . 278 



B. Enewetak Atoll 292 



XI. Acknowledgements . . . . . . . . . . . . . . . . 310 



XII. References . . . . . . . . . . . . . . . . . . 312 



I. Morphological Definition of Halimeda 



Opuntia marina. The Sea Garland. 



This dainty plant groweth up from some Rockes or stones, in or 

 neere the Sea, spreading sundry flat, thicke, short and round leaves, 

 one set on the toppe of another, and some also growing from the sides, 

 forming branches of leaves leaning downewards, each being as it 

 were strung on a thred which yet is scarce to be discerned, like as a 

 Country Garland of field and corne flowers, are used to be made to 

 decke the Country houses, and their places of sport, so that the whole 

 plant seemeth to be made of nothing but strung leaves, bearing a 

 large yellow flower at the toppe saith Bauhinus, but I much doubt he 

 taketh that supposition from the Ficus Indica Americana, the lower 

 leaves are somewhat browne, the rest are whitish greene, and those 

 that are new sprung are greene, and all of them smooth and shining, 

 even kept betweene papers for a long time, and of a saltish taste, yet 

 by long time growing rougher and full of wrinckles, but still tough 

 and not brittle like Corall or Coralline, and growing soft againe 

 steeped in water, yet still very salt. 



Parkinson (1640) 



Over 300 years ago Parkinson provided this first English description 

 of a Halimeda, calling it Opuntia marina, the sea garland. With prose 

 and drawing (Fig. 1), he so clearly captured the essence of the only 

 species then known, H. tuna of the Mediterranean, that his words seem 

 an appropriate introduction to this entire genus of green, calcareous 

 marine algae. 



