54 Scientific Proceedings, Royal Dublin Society. 



Scro2Jliulayi((ceae. 



Species tested, 35. Of these 24 sauk at once, and 7 more within 



an hour. There remain only Pedicularis pahisiris, which floats for over a 



month, and BhinantJms Crista-Galli, a sample of which sank within a fortnight. 



Q-uppy says the latter is variable in buoyancj^, and gives it a period of over 



6 months. The large number which have no buoyancy include several 



marsh-plants. 



Labia tae. 



Species tested, 29. Variable, but only three float for over a week. These 

 three varied much in buoyancy: — Mentha pubeseens, 6J days (mihi) to over 

 6 months (Guppy) ; Lycopns europaeus, 2J days to over 15 months ; Stachys 

 palustris, 1-6 months (Guppy) to over 15 montlis (mihi). The remaining 

 26 species in my list include only one marsh-plant, ScuteUaria minor. 



Polygonaceae. 

 Species tested, 18. Polygonums vary much in buoyancy, and Docks still 



more. 



Eupliorliaceae. 



Species tested, 12. Variable, the most buoyant species being the 



maritime Euphorbias. 



Amentaceae. 



Only 6" species tested. Very variable. 



Typhaceae. 

 Typhas float for some days, Sparganiums for many months. 



Naiadaceae. 

 Six Pondweeds tested by me showed a very uniform buoyancy of 1 to 

 2^ days, but one of these, and three out of six other species tested by Guppy, 

 floated for many months. Naias, Ruppiia, Zannichellia, and Triglochin have 

 all a short period of flotiition. 



Orclddaceae. 

 Species tested, 9. Very variable, buoyancy ranging from in Neofinea 

 intacta to over 15 mouths in Epipactis longifolia. 



Liliaceae. 

 Species tested, 12. Buoyancy very low. The bulbils of Alliums sink at 

 once, as do the fleshy fruits of Convallaria and Polygonatuni. 



Juncaceae. 

 Species tested, 13. Eleven species of Jiuicus all sink at once, excepting a 

 second sample of J. acutus, which floated li day. 



