170 BRITISH SEA-WEEDS. 



inner series large, longitudinal, those of the outer vertical, 

 in few rows. Spore-threads very numerous, radiating from 

 a basal placenta and forming a compound nucleus in mar- 

 ginal, nearly spherical, closed conceptacles ; tetraspores 

 zonate, immersed in the frond, or in marginal lobes. — Eho- 

 DOPHTLiis, from the Grreek rhodeos, rosy, and pJiyllon, a 

 leaf 



This is another division of the old genus Rhodymenia, 

 consequent on the new arrangement^ according to fructi- 

 fication. It differs from the reformed genus Rhody- 

 menia, in the structure of the spore-nucleus, and in 

 having zonate tetraspores. 



Rhodophyllis bifida. The cleft Rhodophyllis. 



Fronds growing in tufts, from one to four inches high, 

 transparent, without veins, forbedly divided from the base, 

 of a brilliant carmine colour. Spores in globose, stalkless 

 conceptacles, which are usually numerous on the margin of 

 the frond ; tetraspores oblong, marked with three transverse 

 lines, arranged in patches in the upper segments. 



This is a very variable plant, and is unfortunately so 

 rare that it is difficult to obtain a series of the different 

 forms. It grows on rocks, etc., in deep water, and is 

 sparingly distributed round the coasts of Great Britain, 

 Ireland, and the Channel Islands. It is a summer 

 annual. Dr. Harvey describes two varieties. One of 

 these, var. /3. ciliata, has since been raised to the 

 rank of a species, and is described below. The other 

 is " var. 7. incrassata. Frond thicker than usual, 

 shrinking, and - turning to brownish-red in drying, 

 broad; segments cruciate, proliferous, or ciliate at the 

 margin." 



