GELIDIACEyE. 



115 



SYNOPSIS OF THE NORTH AJIERICAN GENERA. 



SxjBOUDER 1. Gelidie^. Conceptaclcs divided into two cells by a longitudinal 

 axial placenta which bears spores on both surfaces. 



I. Gelddium. Frond compressed, rigid, decompound-pinnate. 



Suborder 2. Solierie^e. Conceptades having a central, fibro-cellular placenta 

 connected with the walls by slender filaments, and bearing spores on all sides. 



II. EucHEUMA. Frond terete, cartilaginous, horny when dry, shrub-like. Concep- 



tades ovate, external, sessile on the rainuli. 



III. SoLiERiA. Frond terete, succulent, flaccid. Conceptades half immersed in the 

 substance of the filiform branches. 



Suborder 3. Hypneace^. Conceptades traversed by arachnoid filaments, to which 



clusters of spores are attached. 



IV. Htpnea. Frond filiform, much branched ; branches virgate, clothed with 

 subulate ramuli, their apices often hooked. 



1. GELIDIUM. Lamour. J. Ag. ref. 



Frond firmly cartilaginous, linear, compressed, decompound-pinnate. Substance 

 very compact, composed of three strata ; the axis of densely interwoven, longitu- 

 dinal, tenacious filaments, formed of very long, cylindrical cellules ; the intei'mediate 

 stratum of small polygonal cellules set in diverging lines, the j)eriphery of minute 

 cellules arranged in inoniliform filaments at right angles with the axis. Conceptades 

 immersed in the ramuli, prominent on both surfaces, two-celled ; the dissepiment 

 longitudinal, connected with the walls of the cavity by slender filaments. Spores 

 pear-shaped, on slender funiculi, attached to both surfaces of the medial dissepiment. 

 Tetraspores cruciate, immersed among the surface cellules, in subdefined sori near 

 the ends of the ramuli. 



The frond is distichous, almost always pinnate, rarely subdichotomous with pin- 

 nated lesser branches. It is very narrow, compressed or two edged, rarely quite 



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