laurenciacejE. 123 



branched, constricted at intervals of once or twice their 

 diameter. Spores in prominent, conical conceptacles scat- 

 tered over the branches and branchlets. The constrictions 

 are most distinct in the lesser branches and branchlets. 



This plant, which was formerly included in the genus 

 Chylocladia, grows parasitically on small algse in tide- 

 pools near low- water mark. It is by no means common, 

 but has been found on most parts of our coasts. It is 

 very abundant in North America. 



Genus LXVI. LOMENTARIa- 



Frond tubular, constricted at regular intervals, divided 

 internally by transverse, membranous walls. Spores obco- 

 nical, with very short stalks, arranged on a dense globose 

 nucleus in spherical conceptacles which have no orifice ; 

 tetraspores tripartite, scattered among the surface-cells of 

 the branches and branchlets. — Lomentaria, from the Greek 

 lomos, a cross-line. 



This genus, like the last, is comparatively new to the 

 student of British Sea-weeds. It contains the remainder 

 of the species which were formerly called Chylocladia. 

 In external appearance it much resembles Champia ; but 

 the different shape of the conceptacles, the absence of 

 the terminal pore, and the globose arrangement of the 

 spore-nuclei are too important characters to permit the 

 two genera to be combined. 



Lomentaria kaliformis. Whorled Lomentaria. 



Frond almost gelatinous, hollow, having a pyramidal out- 

 line, from six inches to nearly two feet long ; main stem un- 

 divided, constricted, suddenly tapered at the base, from 

 one-eighth to one-fourth of an inch in diameter ; branches 



