RED SEAWEEDS 85 



SUBORDER EHODYMENIEJE 

 GENUS Rhodymenia 



(" Red membrane ") 



R. palmata ( u hand-shaped "). The plant commonly known as dulse. 

 Frond rises from a disk in a short cylindrical stem which spreads into a 

 thin, broad, fan-shaped membrane six to twelve inches long and four to 

 eight inches wide at the top ; deeply and irregularly cleft into many 

 wedge-shaped segments ; margin usually entire, but often with leaflets ; 

 ends of segments indented, showing where divisions will ultimately 

 occur ; color dark purplish-red. It grows on rocks and on alga? below 

 low-water mark, and is common on the New England and California 

 coasts. This is an edible alga, and, like Chondrus crispus, is an article of 

 food in seaports. (Plate XXII.) 



GENUS Lomentaria 



L. Baileyana. Fronds two to five inches high ; grows in tufts ; 

 filaments tubular, irregularly branched; branchlets often all on one 

 side ; branches and branchlets curved or arched, and tapered at both 

 ends ; color brownish-red. It is found washed ashore from Cape Cod 

 southward. (Plate XXII.) 



GENUS Champia 



C. parvula. Frond two to six inches long, irregularly branched ; 

 grows in tufts; filaments hollow and constricted, so that they appear 

 somewhat like a string of beads ; color brownish-purple. It is found 

 washed ashore from Cape Cod southward. (Plate XXIII.) 



GENUS Chylocladia 



C. articulata. Frond filamentous, three to twelve inches long, 

 hollow, constricted at intervals ; branches emanate from constricted 

 ioints ; has the appearance of a series of pink, delicate, oval sacs. 

 (Plate XXII.) 



GENUS Plocamium 



P. cocdneum (" scarlet"). Frond a flat, semi-cartilaginous main 

 stem one eighth of an inch, or less, wide, three to eight inches long, with 

 alternate branches of unequal length emanating from the edges j 

 branches have alternate branchlets arranged in groups of three or four 

 in a row ; branchlets have pinnulae on the upper side, like the teeth of a 

 comb (this peculiarity in branching makes the genus easy to identify) ; 

 color dark lake-red. It is not found on the eastern coast, but is plenti- 

 ful in California. (Plate XXIII.) 



SUBORDER DELESSERDEJE 

 GENUS Nitophyllnm 



N. laceratum. Frond expands from narrow base and divides almost 

 at once into long, narrow, strap-shaped segments ; minute leaflets, show- 



