FLOR1DEJE. 277 



Order Rtiodomelea, of which Dasya and Polysiphonia are common 

 genera. 



Order Chylodaliece, represented by only two Californian species. 



Order Sphcerococcoidece, represented abundantly by species Delesseria. 



Order Corallinece, containing plants which are remarkable for the 

 large amount of calcium carbonate they contain. CoraUinais abundant. 



Order Gelidiece, represented by Gelidium. 



Order Hypnece, including only a few species of one genus Hypnea. 



Order Rhodymeniew, of which Rhodymenia, and Lomentaria are com- 

 mon genera. Rhodymenia palmata, the " Dulse " of our coasts, is used 

 as human food. 



Order Spongiocarp'.ce, with one species of Polyides. 



Order Squamariece, with one species of Peyssonnelia. 



Order Batrachospermcce, to which Nemalion (Fig. 185, B) belongs. 



Order WrangeliecB, with two species of Wrangelia. 



Order Oigartinece, of which Chondrus crispus, the Irish moss so 

 largely used for food, for making blanc mange, etc., is the best-known 

 of the many species on our coasts. 



Order Cryptonemiece, represented mainly on our Southern and Pacific 

 coasts. Schizynemia edulis, of Europe and our Western coasts, ia 

 used as human food. 



Order Dumon'iem, to which Halosaccion of our Eastern coast belongs. 



Order Spyridiem, represented by Spyridia of our Eastern coast. 



Order C'eramiece. This order contains algse " which are either strictly 

 monosiphonous (i.e., composed of a single tube) and filiform, or which 

 are more simple in their structure than others, approaching in this re- 

 spect the Confervacese. It abounds in species which display the most 

 exquisite combination of ramification and coloring." A large portion 

 of our marine flora is composed of individuals of this order, as " they 

 abound on our coasts in every little rocky pool, onevery piece of wood- 

 work exposed to the waves, on rocks and stones, and, above all, on the 

 stems of the larger or firmer algae, or even on marine Phanerogams, 

 which they fringe in the most exquisite way with every shade of red, 

 from a bright rose to purple. "f 



Lejolisia (A, Fig. 185) and Dudresnaya (Fig. 186) are genera of this 

 order. Callithamnion is represented by many species on both our At- 



Report of the U. 8. Fish Commissioner for 1875. It is modified from 

 Thuret's arrangement. The arrangement of the orders and the group- 

 ing of genera into orders are not based upon sexual characters, and con- 

 sequently must be regarded as to a considerable extent artificial. The 

 first-named orders in the list are higher than those that follow. 



f " Introduction to Cryptogamic Botany," by M. J. Berkeley, 1857, p. 

 178. The student is also referred to Harvey's " Nereis Boreali-Ameri- 

 cana," a "Contribution to a History of the Marine Algre of North 

 America," published by the Smithsonian Institution, 1852 to 1858. 



