tatives in Australia, and these are of the humble sort. It is 

 remarkable, among Bhodospermccs, for occupying either littoral 

 rocks at the extreme edge of high -water, or the estuaries of 

 of rivers. Some species occur even in fresh-M^ater streams, at a 

 considerable distance away from the sea ; while one is quite ter- 

 restrial, subject merely to the occasional dash of sea-spray. 



Fig. 1. BosTRYCHiA MIXTA, On stone, — the natural size. Fig. 2. Fronds of 

 the same. 3. Part of a branch, cross section : — magnified. 



Plate CLXXVI. (B.) 



BOSTHYCHIA RIVULARIS, Haw. 



BosTRYCHiA rivulans; stems (subuncial) capillary, bipinnate ; pinna? disti- 

 chous, alternate, patent, tessellated with subquadrate cells ; pinnules 

 subdistant, simple or sparingly ramulous, attenuate, marked with 

 2-3 rows of oblong cells ; conceptacles ovate ; stichidia incurved. 



B. rivularis ; caulibus (subuncialibus) capillaribus bipinnatis, pinnis distichis 

 alternis patentibus cellulis quadratis tessellatis ; pinnidis subdistantibus simpli- 

 cibns V. ramuligeris atteniiatis cellulis oblongis 2-d-serialibus notatis, concep- 

 taculis ovatis, stichidiis incurvis. 



BosTRYCHiA rivularis, Earv. Ner. Bor. Anier. v. 2. p. 57. 1. 14 B.; Alg. Austr. 

 Bxsic. n. 147. 

 Hab. On sticks, roots, and grass, etc., near the estuaries of tidal rivers, 

 or in brackish water near the sea. In the river Mov, Port Fairy, 

 Victoria, W. H. H. 

 Geogr. DisTR. Victoria. Hivers on the east coast of North America. 



Descr. Fronds \-\ inch long, forming patches or tufts, rising from creeping 

 filaments. Stems erect, bipinnated, with subdistant, alternate branches, 

 forming a frond of ovate outline. Pinnules siiuple or forked, or alternately 

 ramulous, with few ramuli, acute or acuminate. Cells in one row, about 

 6 (or 8) in the circle ; those of the ramali once and a half to nearly twice as 

 long as broad, those of the main stems nearly square, all with a dark purple 

 endochrome. Stichidia (immature) ending some of the ramuli, generally 

 the lower ones, incurved or falcate. Colour rather a pale purple, varying in 

 intensity as the plant grows in Salter or fresher water. Substance rigid. 

 In drying it does not adhere to paper, and loses both gloss- and colour. 



The Australian specimens here figured seem to agree very 

 nearly with those from North America, with which I venture to 

 associate them specifically. 



Fig. 1. BosTRYCHiA RIVULARIS, ou a piece of stick, — the natural size. 2. A 

 frond. 3. Part of a branch, 4. Cross section. 5. A yo«/«^ stichidium : — 

 ■magnified. 



