GULFWEEDS 203 



stalked air bladders which ])uoy up the plant when 

 rooted, and float it when torn free. The short, thickened, 

 elontrated and clustered axillary branches (receptacles) 

 which contain the conceptacles ma}' be dis- 

 tinguished easil}^ from the spherical air l^lad- 

 ders. There are many species, one of which 

 (Sargassum vulgare) is common along our 

 eastern coast as a low-tide plant, half a meter 

 to a meter long. Another smaller species Fig. 88. 



/-» •/• \ n • '111 Sargassum. 



{bargassum oacciferum) iloats m considerable 

 quantities in the so-called ''Sargasso Sea" of the central 

 Atlantic Ocean. Its proper home is in the West Indian 

 region, where it grows attached to rocks. 



Laboratory Studies. Probably the best Brown Algae for the 

 beginner to take up are Ectocarpus, Laminaria, and Fucus. 



(a) Good material of Ectocarpus for study may be obtained 

 of dealers in laboratory supplies. The specimens should be 

 examined with reference to tlic general form and appearance of 

 the plant body, and especially for the 1-celled, and the many- 

 celled sporangia. 



(/;) Where fresh material cannot be secured, the Kelps may 

 be studied very well from preserved specimens, which can also 

 be obtained from dealers in botanical supplies. 



(c) Study the tissues of Laminaria and other Kelps in cross 

 and longitudinal sections. 



(d) Make sections through the fruiting j)atc]ies and examine 

 the sporangia and ''paraphyses," that is, the elongated, 

 intervening protective cells. 



(e) It is helpful to have jars of other Kelps, as Sea Palms, 

 Bladder Kelj)s, Giant Kelps, Leafy Kelps, etc., for macroscopic 

 observation. 



(/) Secure specimens of Rockweeds, fresh, alcoholic, or dry. 

 Fresh ones may easily be found along the beach of the ocean 

 after a storm. AlcohoHc and dry specimens and even living 

 material can easily be procured by purcliase or exclianpe. 

 Make thin cross-sections through the conceptacles in the thick- 

 ened ends of the branchlets. When mounted in water, even the 



