280 ALGiE INARTICULATE. [Dictyota. 



ed with conferva-like (but not jointed) branches, of an olive-brown 

 colour. Branches much elongated and attenuated, except the ultimate 

 ramuli, which are short and remarkably slender. Substance slightly 

 gelatinous, so as to adhere to paper. Fructification, scattered seeds, 

 slightly imbedded in the frond." — From the MSS. of Capt. Carmichael, 

 who has examined this plant with much care in a recent state, I extract 

 the following remarks. — " Fronds gregarious, about the thickness 

 of a bristle, chestnut-coloured, repeatedly branched, branches patent at 

 the base, and beset with tapering flexuose ramuli ; the latter often 

 transversely striated as if jointed. Fructification unknown to me, and 

 I should suppose exceedingly rare, for I have examined hundreds of spe- 

 cimens in vain in search of it. This plant is always more or less 

 clothed with conferva-like hairs, but these are so far from furnishing 

 any aid to a specific character, that there are very few of the smaller 

 Thalassiophytcs without them. It varies prodigiously in length, ranging 

 from one to fifteen feet, the latter proved by actual measurement." 



18. Dictyota. Lamour. Dictyota. 



Frond flat, highly reticulated, membranaceous, dichotomous 

 or irregularly cleft (palmato-flabelliform in D. atomarid). 

 Boot a mass of woolly filaments. Fructification composed of 

 scattered, or variously aggregated, somewhat prominent seeds, 

 on both surfaces of the frond. Greu. Alg. Brit. p. 57. t. 10. — 

 Name, br/,ruov, a net; the fronds, as in the preceding Genus, 

 appearing reticulated when magnified. 



1. D. dichotoma, Lamour. (dichotomous Dictyota); frond olive- 

 green linear dichotomously divided, seeds singly scattered or in 

 small irregular clusters — Grev.Alg. Brit.})- 57. 1. 1 0. — Zonaria ? 

 dic/iot, Ag. Sp. Alg. v. I. p. 133. — Ulva dichot., Huds. — E. Bot. 

 t. t. 774. — (3. intricata; frond very narrow much branched 

 twisted and entangled. Grev. — Zonaria? dichot, (3. intricata, 

 Ag.Sp.Alg.v. I. p. 134. 



In the sea, on the larger Algae and on stones ; not unfrequent. — $. Shore 

 near Dumfries, Dr. Richardson. Plymouth, Mr. Sconce. ©. Summer. — 

 Besides the scattered single seeds on this plant, Mrs. Griffiths finds, at 

 Sidmouth, other specimens " covered with transparent vesicles rising 

 above the surface : as they advance in age, a line of dark grains appears 

 within them, and they at length are filled with capsules, which form 

 groupes, and rise above the surface when ripe. In this state they are 

 extremely rare." ' 



2. D.atomdria, Grev. (sprinkled Dictyota) ; frond olive-brown 

 palmato-flabelliform or cuneate irregularly cleft and laciniated, 

 seeds forming waved transverse lines with intermediate scat- 

 tered ones. Grev. Alg. Brit. p. 58. — D. zonata and D. ciliata, 

 Lamour. — Zonaria atomaria, Ag. Sp. Alg. v. 1. p. 128. — Ulva 

 atomaria,Woodw. — E. Bot. t. 419. 



Marine rocks, chiefly on the east and south of England, as at Cromer, 

 Corton and Gunton ; Sidmouth, Torquay and llfracombe ( Mrs. Griffiths). 



1 Mrs. Griffiths further observes, that there is a mistake in Dr. Greville's 

 Algce Britannicce, (p. 58); as "it was the clusters and vesicles that were first 

 found by me in 1822, and not 'single seeds,' as there printed." 



