Ser. Rhodospebme^. " Fam. Uhodymeniaeea. 



Plate CCXXIII. 



PLOCAMIUM PROCERUM, /.4.. 



Gen. Char. Frond membranaceo-cartilaginous, linear, piano-compressed, 

 pinnately decompound ; the pinnules alternately secund, in pairs or in 

 threes or fours ; composed of two strata of cells ; the inner cells ob- 

 long, longitudinal ; the outer polygonal, coloured, small. Fructifica- 

 tion : 1, concejitacles sessile or pedicellate, hemispherical, with a cel- 

 lular pericarp finally opening by a pore ; sporiferous filaments nume- 

 rous, radiating in several tufts from a basal placenta; 2, tetraspores 

 lodged in proper spore-leaves {stichidia), oblong, transversely zoned. — 

 Plocamium {Lpigb.), from 7r\oKafio<;, a tuft of hair. 



Frons membranaceo-cartilaghiea, lmea?'is, plano-compressa, pinnatim composita, 

 pinnis alterne gemluis ternis qiiaternisve, duplici strata contexto ; cellidis in- 

 terioribus majoribus oblongis longitudinalibus, mperficialibm coloratis minutis 

 polygonis. Fruct.: 1, cystocarpia sessilia v. pedicellata, JiemisphtBrica, peri- 

 carpio celluloso denmrn carpostomio munita, Jila sporigera fasciculata a pla- 

 centa basali radiant'ia foventia ; 2, tetraspora. zonalim dlvisce, in sporopJtyllis 

 propriis nidulantes. 



Plocamium proce^'um ; frond linear, ribless or faintly ribbed, pectinato- 

 pinnate ; pinnae alternately geminate, the lower one and the divisions 

 of the upper from a broad base acuminate, subulate, entire or exter- 

 nally serrulate ; conceptacles axillary, pedicellate, solitary or 2-4 to- 

 gether ; stichidia axillary, tufted, simple, falcate or arched, acute. 



P. procerum ; fronde lineari ecosfata v. subtilissime costata peetinato-pinnata ; 

 pinnis alterne geminis, inferiori laciniisque superioris a basi latiore acuniina- 

 tis subulatis integerrimis v. externe serrulatis ; conceptacuUs axillaribus pedi- 

 cellatis subfasciculatis ; sticJiidiis axillaribus fasciculatis simplicibus falcatis 

 arcuatisve. 



Plocamium procerum, /. Jg. Sp. Alg. v. 2. p. 400. Harv. in Hook. Land. 

 Journ. V. 4. p. 542. Ner. Austr. p. 122. Fl. N. Zeal. v. 2. p. 246. 

 Fl. Tasm. v. 2. p. 318. Kiitz. Sp. Alg. p. 886. 



Var. /8. Mertensii ; pinnaj and their divisions denticulate. 



Var. ^. Mertensii; pinnis pinnulisque denticulatis. 



Plocamium Mertensii, Harv. Ner. Austr. p. 122. /. Ag. Sp. Alg. v. 2. p. 401. 



Thamnophora Mertensii, Grev. Syn. p. xlix. /. Ag. in Linn. v. 15. p. 10. 

 Sand, in PL Preiss. v. 2. p. 193. 



Thamnocarpus Mertensii, Kiitz. Sp. Alg. p. 887. 



Hab. Abundant on the west and south coasts of New Holland. Tas- 

 mania. 



