: 390 DR. LILY BATTEN ON 
Descriprion.— Habit. Plants attaining a length of 30cms., main axis 
often pseudo-dichotomously branched, smaller branches arising alternately, 
the whole being clothed with short spine-like ramuli. Small branches and 
ramuli tapering at the base and apex. Siphons. 8-14 pericentral and large 
central. Colour. Dark red when young, later becoming almost black. 
Anatomy. Articulations no longer than their breadth in the procumbent 
parts, 2-3 times as long as broad in the principal parts of the main branches, 
becoming gradually shorter near the apices. — Pericentral siphons spirally 
curved in the main branches, less so in the smaller branches and ramuli, and 
parallel to the long axis of the branch in the procumbent parts. Attachment 
organ. In the young plant the lowest articulations have fewer pericentral 
siphons, and two or more of the latter are elongated into attachment 
rhizoids with discs at their extremities. After branching has occurred, 
rhizoids are developed from the procumbent parts of the lowest branches 
by proliferation of pericentral siphons. Reproductive organs, Tetraspores 
are intercalary in origin and developed in swollen ramuli.  Cystocarps 
sessile or very slightly stalked and broadly ovate with a large open ostiole. 
Habitat. Occuring on rocks, stones, and shells such as Pecten maximus, 
only exposed at low tide or obtained by dredging. Not common. 
British Records. Orkney, Elgin, Aberdeen, Kincardine, Forfar, Fife, 
Edinburgh, Haddington, Berwick, Northumberland, Yorkshire, Norfolk, 
Essex, Kent, Sussex, Hants, Dorset, Devon, Cornwall, Bute, Treland, 
and the Channel Islands. 
Distribution in Europe. Atlantic coasts. 
2. P. FASTIGIATA Grev. Flora Edinensis, 1824, p. 308. 
Hutchinsia fastigiata C. A. Agardh, Syn. Alg. Scan. 1817, p. 53. 
Ceramium fastigiatum Roth, Catalecta Bot. iii. 1806, p. 157. 
Conferva polymorpha Linn. Syst. Nat. ii. 1765, p. 721. 
(rrammita fastigiata Bonnem. Ess. d'une class. des Hydro. loc. 1822, 
p. 45. 
References. Agardh (2) ii. pp. 67 & 1029; De Toni (22) iv. p. 946; 
Falkenberg (23) p. 149 ; Tobler- Wolff (55). 
Icones. Harvey, Phye. Brit. pl. 299. syn. 127. Kützing, Tab. Phye. 
xiii. 1863, p. 14, tab. 44 (a-d). ^ Ewsiecate. Desmaziéres, exs. no. 
254, 1842.  Crouan, Alg. mar. Finist. no. 307, 1852. Lloyd, Alg. Ouest 
Fr. no. 104, 1854. Wyatt, Alg. Damnon. no. 177. 
DESCRIPTION. 
Habit. Plants about 7°5 ems. in height, perennial, forming 
dense tufts. Branching dichotomous, apices outspread. Siphons. 12-24 
pericentral and large central. Colour. Dark reddish-brown. Anatomy. 
Articulations shorter than their breadth: contents of central siphon 
conspicuously dark in colour, shut down into a flattened mass by thickening 
of the wall in upper and lower parts of the siphon. Attachment organ. 
