460 poNDWEEDs. [March, 



and Pliny compare it with this latter plant, and state that it is 

 " more hairy " than a perfectly smooth plant. 



When Pliny was more read and better understood than he is 

 now, both scholars and sciolists amused themselves in hunting 

 out and exposing his errors, while some of the great Coryphai 

 of those days, like Scaliger, Salmasius, etc., tampered with his 

 text, and, like Procrustes, amplified or mutilated their author's 

 language ad libitum. 



Tragus, Cordus, Fuchsius, Dodonseus, Gerard, and other bo- 

 tanists of the sixteenth century, notice the Pondweeds ; but very 

 little is to be gleaned from their works to help to elucidate the 

 history of these species. 



Caspar Bauhin, in the first half of the seventeenth century, 

 collected (see C. B., ' Pinax^ and ' Prodromus ') as many as ten 

 species of Potamogetons, viz. 1st, P. rotundifolium, P. natans, 

 Linn., and enumerates thirteen botanists in whose works it has 

 a place. 



2nd. P. salicifolia, Potamogeton sive Fontalis et spicata of 

 Lobel, Observ. 174, and P. angustifolium of Gerard. Six authors 

 are quoted as authorities for this species, which is no Potamogeton, 

 but Polygonum amphibium of the modern botanists. 



3rd. Potamogeton longo serrato folio (with long serrated leaf) 

 is said to be P. lucens. 



4th. P.foliis latis splendentibus is P. perfoliatus, Linn. 



5th. P. foliis angustis splendentibus, P. cuspidatus, P. com- 

 pressus, P. gramineus, P. lanceolatus, P. angustifolius, and other 

 modern species, might be representatives of the ancient one. It 

 is P. alterum of Dodoens. 



6th. P. crispis foliis sive Lactuca ranarum. This P. crispus 

 is identified by its vulgar name, " Frog's Lettuce." This is one 

 of the utilities of common or popular names, that they are not so 

 easily altered as the more scientific and descriptive appellations. 



This well-known species has been observed and described by 

 Tragus, Lobel, Clusius, etc. The two last-named authors have 

 given figures of the plant. From these we know that they ob- 

 served the larger form and the smaller one ; or, as we moderns 

 usually express a double but not identical form, they knew the 

 typical species P. cr'ispus, and the variety P. serratus. In those 

 days type had not so extensive a signification as it has now ob- 

 tained. 



