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XII. A Systematic Sevision of the Genus Najas. By Alfred Barton Bendle, M.A., 

 D.Sc, r.L.S., Assistant in Botany, British Museum. 



(Plates XXXIX.-XLII.) ^^ 



Eead 15th June, 1899. 



I. General Introduction. 



1. Historical. 



Db. MAGNUS, to whom we owe an admirable account of the morphology and 

 anatomy of the genus as well as valuable suggestions for its systematic division, 

 gives also, in his * Beitrage zur Kenntniss der Gattung l^ajas ' (1870), an excellent 

 historical introduction, tracing its history onward from Vaillant's description and figure 

 under the name Fluvialis (in Mem. Math. Phys. Acad. Boy. Sci. 1719, p. 13, t. 1, fig. 2). 

 Before this, however, Johann Bauhin (Hist. iii. 779 [1651]) had figured both K marina 

 and N. minor under the name Fluvialis Fisana, foliis denticulatis, and Plukenet in his 

 ' Almagestum ' (304, t. 216, fig. 4), in 1696, described and figured N. marina as a species of 

 Fotamogetmi {Fotamogeiton fluviale Sargazo simile, liicens^ foliis margine dentatis). 

 Plukenet's plant is preserved in the Sloane herbarium, in the Department of Botany 

 British Museum. Bay (Hist. iii. 121 [1704]) cites Plukenet's species, and also under 

 Fluvialis a second, the Flagellum Christi of Cupani (Hort. Catb. 241 [1696]). On p. 132 

 he describes the latter, which he received from William Sherard, as the plant of the 

 Hort. Cath. Mr. Druce finds the same in Sherard's herbarium at Oxford ; it is a slender 

 form of N. marina. 



Vaillant describes the female flower as a one-ovuled ovary, the male as monopetalous 

 and containing several stamens. He distinguishes two species which he observed near 

 Paris, Fluvialis vulgaris, latifolia, and Fluvialis angiisto longoque folio. The former, 

 which he figures, is our JV. marina, as is presumably also the latter. A third species is 

 Bay's Fluvialis, and is therefore again N^ marina. Micheli (Nov. PL Gen. 11 [1729]) 

 also has three species, male and female plants of K. maHna being described respectively 

 as 4-seeded and 1-seeded species ; the third is N. minor. He gives good figures of the 

 habit, and is the first to separate the two species which Bauhin had confused. 



Linnaeus founded the genus Najas in his ' Genera Plantarum ' (no. 701) in 1737 ; and 

 in his * Species Plantarum ' (1015), in 1753, made one species N. marina with two 

 varieties (/3 and y). His varieties are simply Bay's two citations of the same plant, 

 Flagellum CluHsti, and do not refer, as has been supposed, to JV. minor. The specimens 



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