32 L. HILLIS-COLINVATJX 



suggested by Howe. In this way Hillis' monograph resolved both 

 differences of usage between America and Europe : the correct name 

 for Barton's H. incrassata, and the specific status of H. monile and 

 H. simulans. 



The preceding brief account of the history of Halimeda shows that 

 the major collections which had been examined critically by the 1930s 

 had come, first from the Mediterranean, then the Dutch East Indies, 

 followed by the West Indies. Not until the 1940s were concentrated 

 studies made of Halimeda in Pacific atolls. The Japanese phycologist 

 Yamada (1941) described a new species micronesica from the Caroline 

 Islands. This taxon is particularly noteworthy because it possesses a 

 fourth pattern of nodal medullary filaments (see discussion of f. ovata 

 earlier on p. 29). The medullary filaments of this species do not 

 fuse at the node, but pass unchanged, except for branching, from one 

 segment to the next (Table III, Type 4). 



In 1946, William Randolph Taylor of the University of Michigan 

 participated in "Operation Crossroads", the detailed scientific study of 

 the Marshall Islands before and after atom bomb trials. Prominent in 

 his collection of the vegetation of four of the atolls was a large and 

 exciting series of Halimeda plants which were included in his book 

 "Plants of Bikini" (Taylor, 1950). Some were new species, and one of 

 them, fragilis, was a second species with unfused medullary filaments. 



By 1950, then, the species total of Halimeda, counting monile and 

 simulans as species rather than varieties, was about three times that 

 accepted by Barton. A quiet outburst of Halimeda data had occurred, 

 and, as a result, Barton's monograph could no longer be used exclusively 

 to study the Halimedae of any one region. It remained a useful 

 introduction to the critical taxonomy of Halimeda, but was not the 

 definitive work on the genus. 



In the mid-1950s Hillis, later publishing as Colinvaux and Hillis- 

 Colinvaux, began working on Halimeda. Studying at the University of 

 Michigan she had available the university's herbarium containing 

 extensive collections from several Caribbean Islands as well as from the 

 Marshall Islands. Curators of the New York Botanical Garden and the 

 British Museum (Natural History) lent considerable portions of their 

 large Halimeda holdings, the former collection containing much of 

 Howe's and some of Borgesen's material, the latter including important 

 specimens examined by Barton, although the bulk of Siboga expedition 

 material, housed in the Rijksherbarium, was examined several years 

 later in Leiden. A loan from the University of California provided 

 additional plants from Pacific reefs. The collections, supplemented 

 with other important although smaller loans and some live material, 



