1-2 feet long or more, 2-8 inches wide, extremely variable in shape. The 

 primitive form appears to be oblong, or obovate-oblong, tapering at base, 

 either blunt at the extremity or tapering to a subacute point. Sometimes 

 it is quite simple, with the margin variably indented or sinuate; more fre- 

 quently the marginal teeth are developedinto leaf-like lateral lobes, l-6inches 

 long, and ^-1^ inch wide. Specimens that bear tetraspores are very gene- 

 rally deeply divided, and sometimes cleft nearly to the base into numerous 

 broadly-lanceolate segments, which are then either quite entire and flat, or 

 else margined throughout with lateral leaflets. The surface is generally 

 quite smooth and glossy, but is sometimes buUated, and occasionally 

 roughened by small processes. The cysiocarps are extremely numerous, 

 and profusely scattered over the whole frond; they are hemispherical, thick- 

 walled, and contain a dense nucleus within a large cavity. The tetraspores 

 are triangularly parted, and form cloudy patches, dispersed over the frond. 

 The colour varies from a dull livid-purplish to a rather bright but pale blood- 

 red : it soon fades on exposure. The substance is thickish-membranous, or 

 like parchment, shrinking in drying, and imperfectly adhering to paper. It 

 bears steeping in fresh-water, without injury, for a considerable time. 



With the structure and fructification of Uliodymenia this spe- 

 cies has much of the habit and extreme irregularity of outhne of 

 an Iridaa or of the broad-fronded Gigariince, such as G. radula. 

 Our figure represents an average form, but many foho plates 

 might be filled to little purpose with varying individuals, with- 

 out exhausting the " sports" of this most sporting plant. Still, 

 there is that general agreement in substance and texture, and 

 that scarcely definable resemblance between all, that make it 

 easy, on the shore, to combine the many shapes under one ideal 

 type. In the herbarium it is not so easy, without comparison of 

 a very extensive suite. Hence single specimens, or a solitary 

 figure, of this plant, can scarcely be said to illustrate it. 



Its nearest affinity is with R. pertusa, of the N.W. Pacific, and 

 M. sancjuinea, of New Zealand. 



Fig. 1. Ehodymenia polymorpha; the natural size. 2. Vertical section of 

 a conceptacle, and of the frond. 3. Spores from the nucleus. 4. Tetraspores: 

 — variously magnified. 



