THE THALLOPHYTES 361 
The dried mucilaginous substance extracted from Gelidium 
corneum or other species of Gelidium (Fam. Gelidiacee) and closely 
related red algz growing in the sea along the eastern coast of 
Asia and along the coast of California constitutes the drug, AGAR. 
Fic. 266.—Gigartina mamillosa. Ss, fruiting body consisting of short projection 
bearing tiny sporangia. (After Strasburger.) 
Agar is a most valuable ingredient in culture media as well as a 
laxative. 
Rhodymenia palmata or Ir1sH Dutse is a purplish-red, flat, mem- 
branous, palmately cleft or dichotomous red alga growing on the 
tissues of other algae along northern shores of the Atlantic between 
the low- and high-tide marks. 
