238 ALQJE CHLOROSPERME^E. [Oscittatoria. 



inch in diameter, blackish-green. Stria closely set, and strongly 

 marked. 



74. LYNGBYA. Ag. Lyngbya. 



Filaments destitute of a mucous layer, free, flexible, elongated, 

 continuous, decumbent. Endochrome (green or purple), 

 densely annulated, and finally separating at the annuli into 

 lenticular sporidia. Named, in honour of H. C. Lyngbye, 

 a Danish Algologist, and author of an excellent work on the 

 Alga of Denmark. 



1. L. muralis, Ag. Wall Lyngbya. Filaments somewhat 

 rigid, thickish, tortuous, interwoven into a bright grass-green 

 stratum. Harv. in Hook. Er. Fl. v. ii. p. 370. Conf. muralis, 

 Dillw. t. 7. E. Bot. t. 1554. 



On damp walls, very common ; and particularly obvious after a 

 shower of rain. 



2. L. majuscula, Harv. Large Lyngbya. Filaments very 

 thick, issuing in long crisped bundles from a blackish-green 

 stratum ; tortuous, simple, or slightly pseudo-branched. Harv. 

 in Hook. Br. FL v. ii. p. 370. Conf. majuscula, Dillw. Sup. 

 t.A. 



In the sea. Bantry bay ; Miss Hutchins. Skerries, Portrush ; 

 Mr. D. Moore. 



75. OSCILLATORIA. Vauch. Oscillatoria. 



Filaments invested by a common mucous matrix, rigid, elastic, 

 oscillating, simple, continuous. Endochrome divided by 

 close, parallel, transverse striae. Named from the curious 

 oscillatory motions of the filaments. The species, which are 

 exceedingly numerous and difficult of definition, have hitherto 

 been much neglected by British, and but very slightly 

 touched on by Irish botanists. The late Capt. Carmichael, 

 who studied the genus with great care and success, has 

 added many new and curious species to the Scottish Flora, 

 most of which may probably be found in our own country, if 

 carefully looked after. In the following descriptions the 

 colour of the strata always refers to the appearance pre- 

 sented to the naked eye : that of the filaments, to what they 

 appear when viewed with a microscope. 



* Fasciculatae ; filaments collected into close, rigid, agglutinated 

 fascicles. 



1. O. Friesii, Ag. Fries' Oscillatoria. Stratum bright- 

 green, bristling with the elongated, rigid, erect, tooth-like fas- 



