78 SPOKOCHNACE^.— Dbsmaeestia. iv. 



substance. Colour, when growing, a fine chesnut-olive, quickly changing to ver- 

 digris green when removed from the water. Substance tender, soon decomposing. 



2. Desmarestia aculeata, Lamour. ; stipes short, cylindrical ; stems (or primary 

 branches) elongate, flattish, bi-tripinnate ; pinnaB and pinnulse alternate, very narrow, 

 tapering to the base, either fringed with opposite tufts of bright green filaments or 

 margined with awl-shaped, alternate spines. J. Ag. Sp. Alg. vol. 1,J9. 167. Kiitz. 

 Sp. Alg. p. 571. ffarv. Phyc. Brit. t. 49- Grev. Alg. Brit. t. 5, /. 2, 3. Fucus 

 aculeatus, Linn. Turn. Hist. Fuc. t. 187- Fng. Bot. t. 2445. (Tab. IV. B.) 



Hab. On submerged rocks and stones at low-water mark and at a greater depth. 

 Very abundant on the east shores, from our northern limits to Long Island Sound (at 

 least). Probably also on the N.W. coast (being found at Kamtschatka). (v. v.) 



Fronds from one to six feet in length, about half a line in width, compressed or 

 flattish, excessively branched and bushy ; the branches usually alternate, rarely 

 opposite, erect, tapering to their base and apex, as do also all the lesser divisions. 

 When young the branches are of a tender substance, soft to the touch, and clothed 

 at intervals of about a line with opposite pencils of finely divided byssoid filaments 

 of a beautiful yellow green colour. In older fronds these delicate filaments fall 

 away, and the branches become rigid and tough, while subulate spinelike alternate 

 teeth are developed from the margin at every three or four lines apart. In transi- 

 tion specimens both spines and filaments are found together, the former being com- 

 paratively soft. Colour pale olive when young, foxy brown or sometimes very dark 

 when old. 



At different ages this plant may readily be taken by a student for two species, 

 as indeed it was by Linnaeus himself. 



3. Desmaeestia ligulata, Lamour. ; frond flat, Avith a slender, more or less evident 

 midrib, repeatedly pinnate ; pinnae and pinnulte opposite, oblong or lanceolate, 

 tapering to both ends. /. Ag. Sp. Alg. vol. 1, p. 169- Kiitz. Sp. Alg. p. 572. 

 Harv. Phyc. Brit. t. 115. Fucus ligulatus, Turn. Hist. t. 98. E. Bot. 1. 1636. Fucus 

 herbaceus, Turn. Hist. t. 99. Desmarestia herbacea, Auct. 



Hab. North West Coast, Mr. Menzies. (v. v.) 



The ordinary European form of this species, figured in Phyc. Brit.t. 115, has not 

 yet been noticed on the American coast, except at Cape Horn (!), but may be 

 expected to occur on the shores of some part of British America. The plant 

 recorded above as having been found by Mr. Menzies on the N. W. coast has 

 broader leaves, but, to judge by Mr. Turner's figure, is scarcely otherwise to be 

 distinguished. The following is his description of Mr. Menzies' specimens : — 



