GRACILARIA. 129 



granular matter ; those of the surface minute, forming dense- 

 ly-packed horizontal filaments. Fructification: 1, convex 

 tubercles (coccidid), having a thick pericarp composed of 

 radiating filaments, containing a mass of minute spores on a 

 central placenta ; 2, tetraspores imbedded in the cells of the 

 surface. Name, from gracilis, slender. 



1. multipartite^ Clem. ; frond cartilagineo-membranace- 

 ous, tender, semi-transparent, brittle, dull purplish-red, 

 deeply cleft in an irregularly dichotomous or palmate man- 

 ner ; the branches linear-wedge-shaped ; the apices acute ; 

 tubercles conical, prominent, scattered over the surface. 

 Harv. Phyc. Brit. t. xv. Rhodymenia polycarpa, Grev. Alg, 

 Brit. p. 87 ; Hook. Br. Fl. ii. p. 289 ; Wyatt, Alg. Damn. 

 No. 108 ; Spharococcus polycarpus, Grev. Crypt, t. 352. 



On rocks and stones in the sea; very rare. Perennial? August and 

 September. Shore under Tail's Hill, Plymouth, Miss Hill, abundantly, 

 Rev. W. S. Hore, Dr. Cocks, &c. Whitsand Bay, Dr. Jacob. Salcombe 

 Bay, Mrs. Wyatt. Root a thin spreading disk. Frond 4 12 inches high, 

 cleft nearly to the base in an irregularly dichotomous manner ; sometimes 

 vaguely or palmately divided ; sometimes having the principal divisions 

 cleft into numerous secund, jagged segments ; the branches liueari-wedge- 

 shaped ; apices acute. Capsules large, spherical, prominent, abundantly 

 scattered over the frond. Granules very minute, imbedded in the frond 

 over its entire surface. Substance, according to Mrs. Griffiths, " when 

 fresh, thick, cartilaginous and tender, semi-transparent and very brittle, 

 and most nearly resembling that of Lau. pinnatijida ,-'' when dry, it be- 

 comes tough and shrinks considerably. Colour a dull purple, becoming 

 redder iu fresh water, pinky towards the tips. 



2. G. compressa, Ag. ; frond succulent, brittle, somewhat 

 compressed, alternately or sub-dichotomously branched ; 

 branches long and mostly simple, tapering to a fine point ; 

 tubercles ovato-globose, sessile, scattered over the branches. 

 Grev. Alg. Brit. p. 1 25 ; Hook. Br. Fl. ii. p. 299 ; Wyatt, 

 Alg. Damn. No. 25 ; Harv. Phyc. Brit. t. ccv. Sphcer. 

 lichenoides, Grev. Crypt, t. 341, (not of Ag.) 



Thrown up from deep water ; very rare. Annual. August. Sidmouth, 

 Mrs. Griffiths and Miss Cutler. Fronds several from the same disk-like 

 base, 6 12 inches long, from half a line to a line and a half in diameter, 

 cylindrical, or somewhat compressed, either rising with a simple stem, 

 and set with long alternate branches, all of which are much attenuated at 

 base and apex; or divided near the base in a more or less dichotomous 

 manner, the chief divisions alternately branched, and either naked, or fur- 

 nished with a series of long, subulate, alternate or secund ramuli ; thus 

 the frond is partly dichotomous, partly pinnate. Tubercles sessile, large 

 and prominent, scattered plentifully over the branches. Tetraspores mi- 

 nute, imbedded in the branches of distinct plants, tripartite or cruciate. 



K 



