. \MI LI IT.. 1 1") 



Callithamnion Ralfsii, Harv. 



Hob. South of England. On mud-covered rock-, in 

 tween tide-marks. \w\ rare. Perennial? 

 T<> the naked eye this species, unless closely examined, 

 resembles a ragged specimen of C. Jloridul 

 when compared under a lens with thai plant, the two are 

 seen to be abundantly different. The short opposite ramuli 

 which feather the ends of the branches of < ' barbatw 

 which an 4 mosl abundanl in summer specimens, though 

 perhaps always to be found in degree, form the st] 

 mark of the Bpecies. 



254. Pluma {The feather Callithamnion) j Btems rising 

 creeping filaments, erect, subsimple or alternately branched; 

 branches naked below, the upper half pinnated with short, 

 erect, closely set, opposite ramuli ; articulations from two to 

 four times as long as broad ; tetraspores globose, either ter- 

 minating shortened pinnules, or placed on little stalks near 

 the base of the pinnule, Ag. Sp. Alg. v. -. p. 162. (Ai LAS, 

 PL LYIII. Fig. 267.) 



Callithamnion Plumula, var., Lyngb. Ceramium Pluma, Ag. 



Conferva Pluma, Dilfao. 

 Hah. Parasitical on the Btems of Laminaria digitata z rather rare. 



Annual. Summer. 

 A beautiful little parasite, pretty much confined to the 

 stems of Laminaria digitata, which it sometimes clothes 

 in patches, looking like shreds of crimson velvet. Dill- 

 wyn's figure represents the uprighl stem as perfectly sim- 

 ple, the whole plant strictly resembling a little feather. I 

 have sometimes mot it bo, hut it is more usual to find one 

 or two branches rising from the lower par:, as shown in 

 our figure. C, Pluma is nearly allied to C. Turneri, from 

 which it chiefly differs in the smaller size and shorter arti- 

 culations, and in having the lower part of the stem and 

 branches constantly naked. 



255. arbuscula [The bush Callithamnion) ; Btems naked below, 

 inarticulate, robust, cartilaginous, the main division* 

 with shorter branches, which are aenselj clothed on all - 

 with minute, imbricated, pinnated ramuli (plumules) ; ulti- 

 mate pinnules simple or forked, recurved, acute, articu 



the articulations twice as Long as broad; tetraspores glo- 

 wile on the upper cdm- of the pinnules, 

 Lyngb. it - V\. LVI1 



262.) 



