238 TETRANDKIA— TETRAGYNIA. Ruppia. 

 82. RUPPIA. Ruppia. 



Linn. Gen. 6$. Juss. 19. FL Br. 198. Lam. t. 90. Gcertn. *.84. 

 Buccaferrea. Mich. Gen. t.35. 



Nat. Orel, see n. 81. 



Cat. and Cor. none. Anth. 4, sessile, irregularly quadran- 

 gular, depressed, bursting by a horizontal transverse fis- 

 sure. Germens 4, occasionally 5, turbinate, at lengtli 

 stalked. Styles none. Stigmas obtuse, depressed in the 

 centre. Seeds 4, naked, ovate, obliquely pointed, convex 

 at one side, bluntly keeled at the other, each elevated on 

 a stalk, 4 or 5 times its own length. 



Habit of Potamogeto?i, from which it differs in the want of 

 a corolla, in the posture as well as shape of the anthers, 

 and in the stalked seeds. But Linnaeus surely errs in using 

 the term spadix here, for what the former genus shows 

 to be ajlower-stalk. Impregnation in Ruppia takes place 

 within the sheath of the leaf, and the seeds are subse- 

 quently raised above the water to ripen ; just the reverse 

 of Potamogeton. 



1. R. maritima. Sea Ruppia. Tassel Pond-weed. 



R. maritima. Linn. Sp. PI. 184. IVilld. v. 1.717. FL Br. 198. 

 Engl. Bot.v.2. t. 136. Hook. Lond. f.50. Scot. 59. Light/. 124. 

 t. 8.f. 1. Dicks. H. Sicc.fasc. 17. 9. 



Potamogiton maritimum, gramineis longioribus foliis, fructu fere 

 umbellate Raii Syn. 134. t. 6.f. 1. 



P. maritimum pusillum alterum. Pluk. Phyt. t. 248./. 4. 



Fucus ferulaceus. Ger. Em. 1573./. 



Tassel Pond-weed. Petiv. H. Brii. t. 6.f. 1. 



Buccaferrea maritima, foliis acutissimis j etiam foliis minus acutis. 

 Mich. Gen. 72. t.35. 



In salt-water ditches. 



Perennial ? August, September. 



Herb submersed. Roots fibrous, in tufts, from several of the lower 

 joints of the long, slender, round, much branched, leafy stem. 

 Leaves alternate, linear, extremely narrow, more or less acute, 

 channelled, single-ribbed from about the middle upward, entire ; 

 dotted with brown or purple towards the edges ; clasping the 

 stem with their sheathing, somewhat dilated, base. Spikes usually 

 2-flowered, on short, solitary, axillary stalks. FL alternate, ver- 

 tical, as distinct on their common stalk as those of any Potamo- 

 geton, and inclosed within the sheath of the neighbouring leaf, 

 as it appears, till impregnation is accomplished ; my account in 

 Engl. Bot. being, in this particular, incorrect. Professor Hooker 

 has rightly explained the process. After flowering, thejtower- 



