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XV. Remarks on the Nature and Propagation of marine Plants. 

 By Lieut. Col. Thomas Velley, F. L. S. 



Read May 7, 1799. 



HAVING, in a former inquiry into the mode of propagation pe- 

 culiar to marine plants, attempted to point out fome material 

 errors, which accompanied the theories of Gmelin and Gaertner, by- 

 proving, that the membranaceous Fuci, which the former confidered 

 as merely proliferous, derived their origin from adlual feeds ; and 

 that the numerous tribe of Conferva, which Gsertner, upon a very 

 flight and fuperficial examination, has dogmatically declared to be 

 deftitute of feminal increafe, were beyond a doubt dependent uport 

 the fame general law of Nature, for their propagation, as the Fucus: 

 I fliaH now lay before this Society fome further obfervations upon 

 the fubjedt, arifing principally from an examination of the recent 

 theories that have very lately made their appearance in the world. 

 It may not however be foreign to the purpofe, to inveftigate the de- 

 finition of the generic character prefixed by Linnaeus to the Fucus, 

 and which does not appear to be clearly ftated. 



In the Genera Plantarum he defines the fuppofed male flower as 

 follows: " Veficulas glabrae, cavaj, pills intus afpcrfaz;" rendered by 

 the Lichfield Society, " Veficles fmooth, hollow, fprinkled with 

 hairs within;" and in the Nereis Britan. "Bladders fmooth; hol- 

 low, interfperfeil within with foft hairs," Linnaeus, however, cau- 

 tioufly introduces this definition upon the authority of Reaumur ; 



Vol. V. U he 



