34 



A TEXT-BOOK OF BOTAXY. 



cal outgrowths developed on the surface of the fronds. This 

 form is found more abundantly north of Boston than south, but, 

 as Chondnis is collected at Cohasset, Scituate, and other towns 

 south of Boston, it is not seen in commerce in this country. 



RHODYMEXIA, or Irish Dulce, is one of the commonest red 

 sea-weeds in the North Atlantic ( )cean. usually growing with Fucus, 

 Laminaria, and other Alg?e between tide marks and extending 

 into deep water. The fronds are purplish-red, flat, membra- 



Fir,. 17. Gigartina mamdlosa, a red sea-weed closely related to Chondrus crispus, 

 showing a dichotomously branching thallus and bearing at the upper part numerous cylin- 

 drical outgrowths in which the fruit bodies (sporangia) are found. After Kutzing. 



nareous, 15 to 30 cm. in length, irregularly cleft, palmate or 

 diclmt onions, the margin often being marked with numerous 

 -mall divisions. The sporangia occur in scattered patches im- 

 mersed in the cortical tissues of the frond. It is a common article 

 of ruinim-ive and is said to possess anthelmintic properties. 



AGAR-AGAR is derived from several of the marine Algre grow- 

 ing along the eastern roast of Asia, notably species of Gracilaria, 

 irlidiuni. and ( iloiopellis. It is a mucilaginous substance which 

 i- extracted from the sea-weeds, and is used extensively as a 



