84 POLYSIPHONIA. 



main thread alternately or sub-dichotomously branched, rather stouter than 

 the branches, which are frequently long and much divided ; lesser divisions 

 more or less furnished with pencil-like tufts of dichotomously divided 

 ramuli. Joints bi-striate, the stria: frequently crossing, those of the main 

 thread sub-opaque, very short at base, becoming longer upwards, in the 



middle 4 8 times longer than broad, in the lesser ramuli 2 or 3 times. 



Tips of the ramuli truncate, bearing byssoid fibres and antheridia. Cap- 

 sules ovate or globose, plentifully scattered over the ramuli ; granules large, 

 imbedded in the upper ramuli. Mrs. Griffiths finds at Ilfracombe, and 

 Mr. D. Moore at Island Magee, Co. Antrim, a variety which differs from 

 the common state in being less branched, the branches more distant, with 

 much denser and more finely divided pencils of ramuli. 



6. P. spinulosa, Grev. ; " dark red ; branches divaricate, 

 somewhat rigid ; the ramuli short, straight, subulate, divari- 

 cate ; articulations about equal in length and breadth, three- 

 tubed." Grev. Crypt. FL t. 90 ; Hook. Br. Fl. ii. p. 330. 



In the sea ; extremely rare. Annual? Appin, Capt. Carmichael, who 

 only found one specimen. Frond 1 or 2 inches in length, of a dark red 

 colour, much branched, with a rigid and spinulose habit; main branches 

 rather remote, irregular, much divaricated, somewhat flexuous ; ultimate 

 ramuli straight, subulate, almost thorn-like, divaricated like the rest, some- 

 times minutely divided at the apex, and each of the divisions terminated 

 by a long, hyaline, jointed filament. Articulations about as long as broad, 

 striated, with three internal tubes, of a pale brown-pink under the micro- 

 scope. Tubercles (young) " very minute, quite sessile, round, dark red, 

 scattered freely on the branches, and containing several dark granules." 

 Grev. I. c. This is a very rare and little known plant, of which I have seen 

 no specimen save the original one, found by Capt. Carmichael, and now 

 preserved in the Hookerian Herbarium. Dr. Greville's figure is very cha- 

 racteristic. A transverse section of the stem exhibits four large siphons, 

 with smaller secondary ones at their external angles. The Devonshire 

 habitat, given on the authority of Mrs. Griffiths, in our first edition, 

 belongs to Pol. simulans, a plant of very different structure, though very si- 

 milar aspect. 



7. P. Richardsoni, Hook. ; stems cartilaginous, setaceous ; 

 branches alternate, elongated, divaricate, beset in the upper 

 part with very patent, straight, sub-dichotomous ramuli ; ar- 

 ticulations of the stem and branches 2 or 3 times longer than 

 broad, irregularly veined, of the ramuli shorter; ceramidia 

 sessile, globose. Hook. Br. Fl. ii. p. 333 ; Hare. Phyc. 

 Brit. t. x. 



At Colvend, Dumfries, Sir John Richardson. Stems 3 or 4 inches high, 

 rigid, nearly as thick as a hog's bristle at base, branched throughout ; 

 branches alternate, often issuing at right angles. Colour a dull red, be- 

 coming darker in drying. Main articulations marked with numerous, 

 anastomosing, irregular tubes, those of the lower branches 3 5 tubed, of 

 the ramuli 2 or 3 tubed. Capsules sessile, scattered, subglobose, with a very 

 wide aperture. Siphons five in the stem. Of this species nothing is 



