Ser. RHoposPERME. Fam. Chondriec. 
Piate CXLVIII. 
LAURENCIA OBTUSA, Zamour. 
Gen. Cuan. Frond cylindrical or compressed, linear, pmnately branched, the 
apices obtuse; structure cellular, solid. Fruetification of two kinds, 
on distinct individuals; 1, ovate capsules (ceramidia), furnished with 
a terminal pore, containing a tuft of pear-shaped spores; 2, triparted 
tetraspores, imbedded im the ramuli. Laurencra (Lamour.), m 
honour of J. de la Laurencie, a French naturalist. 
Lavrencta obtusa; frond cylindrical, filiform, repeatedly pmnate ; branches 
patent; pinne and pinnule mostly opposite, the ultimate pinnules 
very short and obtuse, sometimes cruciform. 
Laurencta obtusa, Lamour. Ess. p.42. Duby, Bot. Gal. p. 951. Grev. Aly. 
Brit. p.111. J. Ag. Alg. Medit. p.114. Endl. 8rd Suppl. p. 43. Mont. 
Algier. p.92. Hook. Br. Fl. vol. ii. p. 296. Wyatt, Alg. Danm. no. 21. 
Harv. in Mack. Fl. Hib. part 3. p.198. Harv. Man, p. 70. 
LAvURENCTIa intricata, Lame. Ess. p. 43. t. 3. f. 8, 9. 
Lavrencta gelatinosa, Lame. sec. Ag. 
Lavurencta lutea, Lame. sec. Ag. 
LAURENCIA cyanosperma, Lama. Ess. p. 43. 
Cuonprta obtusa, 4g. Sp. Alg. vol.i. p. 340. Syst. p. 202. Hook. FV. Scot. 
part 2. p.105. Grev. Fl. Edin. p.290. Spr. Syst. Veg. vol. iv. p. 341. 
Kiitz. Phyc. Gen. p. 437. 
Fucus obtusus, Huds. Fl. Ang. p.586. Turn. Syn. p. 43. Turn. Hist. t. 21. 
#. Bot. t. 1201. 
Has. Parasitical on the smaller Alge between tide marks. Annual. 
Summer. Not uncommon on the shores of England and Ireland. 
Rare im Scotland. Frith of Forth, Dr. Grevil/e. Ardrossan and 
Arran, Rev. D. Landsborough. 
Groer. Distr. Dispersed throughout the Atlantic and Pacific Oceans, both 
north and south, in temperate and subtropical latitudes. Mediterranean 
Sea. Mauritius. 
Descr. Root, a small disc, with or without accessory fibres. Fronds several 
from the same base, forming dense, globose tufts, from three to six inches 
long, cylindrical, of equal diameter throughout, slender, from a quarter to 
half a line in diameter, furnished with a simple stem, which is closely set 
throughout with very patent or horizontal, often opposite, lateral branches, 
which diminish in length from the base to the apex, so that the whole frond has 
a pyramidal outline. Branches subdistichous, or more or less quadrifarious, 
spirally inserted, repeatedly pinnate; pinnze opposite, patent, the lower 
ones often short and multifid, the middle ones longest, lanceolate and 
simply or doubly pinnate, the upper gradually shorter to the tip. Ulti- 
mate ramuli very short, obtuse, somewhat clavate, simple, or furnished with 
G2 
