688 BOTANY AND PHARMACOGNOSY. 



Description. — Consisting of a number of dichotomously 

 branching, somewhat enlarged segments, becoming emarginate or 

 two-lobed, which arise from a slender, somewhat flattened base 

 about one-half the length of the entire thallus; yellowish- white, 

 translucent, sometimes with fruit-bodies or cystocarps embedded 



Fig. 278. Chondrus crispus attached to a rock and collected at Wood's Holl, Mass. 



near the apex of the segments ; somewhat cartilaginous ; having a 

 slight saline odor and a mucilaginous, somewhat saline taste. 



One part of Chondrus boiled for ten minutes with 30 parts of 

 water yields a solution which gelatinizes on cooling, and is not 

 colored blue by iodine test-solution (absence of starch) ; nor pre- 

 cipitated by alcohol (distinction from true plant gums) ; nor pre- 

 cipitated by tannin (distinction from gelatin) ; nor precipitated 

 by lead acetate (distinguishing it from pectin). 



