80 COLLINS AND HERVEY. 



SARGASSUM Agardh. 



The Sargassa abound everywhere in warmer water; there have been 

 very many species described, and new ones are continually added to 

 the list; undoubtedly there have been many cases where observers 

 from distant regions have described the same species independently 

 and in good faith; ultimately one of the names must give way to the 

 other. On the other hand more conservative botanists have used 

 the name of a well-known species for a form found at a station distant 

 from the home of the species, and sooner or later the later named form 

 will have to be segregated. Whether mistakes made by too radical 

 or by too conservative treatment are more harmful, will probably 

 remain an open question in botanical as in other matters. In our 

 treatment of the Bermuda species, we find in some of them more or 

 less noticeable differences from the species of the same name elsewhere, 

 and we have given an account of the characters of each of the species 

 we recognize, and have drawn these characters from Bermuda speci- 

 mens, not from descriptions of others. 



Key to the Species of Sargassum. 



1. Always floating, without fruit or basal attachment. 2. 



1. Attached, fruiting. 3. 



2. Slender throughout, the -leaves very narrow, with aculeate teeth. 



1. S. natans. 



2. Stouter; leaves lanceolate with triangular teeth. 2. S. fluitans. 



3. Stem densely muriculate or with short proliferations. 4. 



3. Stem not muriculate, or only slightly and occasionally so. 5. 



4. Leaves ovate or broadly lanceolate. 4. S. lendigerum. 



4. Leaves narrowly linear, simple or 1-several times forked. 



3. S. linifolium. 

 5. Fructification long, slender, filiform, loosely branched. 



6. S. Filipendula var. Montagnei. 

 5. Fructification not so slender or elongate. 6. 



6. Receptacles with dentate wings. 8. S. platycarpum var. berrnudense. 



6. Receptacles wingless. 7. 



7. Individual receptacles on slender pedicels. 3. S. linifolium. 



7. Receptacles fertile throughout. 8. 



8. Receptacles forming a dense glomerule. 7. S. Hystrix. 



8. Receptacles repeatedly forked, branches separate. 5. S. vulgare. 



1. S. NATANS (L.) J. Meyen, 1838, p. 185; Borgesen, 1914, p. 7; 

 P. B.-A., No. 2180; S. bacciferum Agardh, 1821, p. 6; Harvey, 1852, 



