ZOSTERA. NAIAS. 4-15 



1. ZOSTERA. Fl. imperfect. Stam. and pistils inserted in 

 two rows upon one side of a spadix. Spath linear, leaflike. 

 Fl. naked. Anth. 1. Ovary 1 ; style 1 ; stigmas 2. 



2. NAIAS. Fl. imperfect, solitary, sheathed ; no perianth. 

 Barren fl. of 1 stamen. Fertile : style short ; stigmas 2 4 

 filiform. 



1. ZOSTE'RA Linn. Grass-wrack. 



1. Z. ndna (Roth) ; 1. linear 1 -veined, ped. filiform, spadix 

 short with 2 5 clasping bands, nuts smooth. E. B. S. 2931. 

 R. vii. 2. Plant small, scarcely 3 in. long. L. slender. Ped. 

 pale-coloured throughout, \ as broad and quite as long as the 

 inilated oblong-lanceolate spaths. Ripe seed shining ulack. 

 Muddy estuaries. P. ? VII. VIII. E. S. I. 



2. Z. marina (L.) ; 1. linear 1 7-veined, spadix without 

 bands, nuts striate. E. B. 467. R. vii. 4. Plant long. L. 

 broad. Ped. rather strong. Ripe seed milky white. Z. angus- 

 tifolla, R. vii. 3, Sy. E. B. 1430, is a slender form growing 

 upon mud, with fewer veins in its 1. and rather longer peduncles 

 which are much compressed and green upwards and narrow 

 gradually into the spadix. In the sea. P. ? VII. VIII. E. S. I. 



2. NA'IAS Linn. 



1. J\ T . marina (L.) ; dioecious, st. dichotomously branched from near the 

 base, 1. linear with many large spinous teeth, sheaths rounded nearly orquite 

 entire, n. solitary male enclosed in a spath, anth. 4-locular, fr. succulent 

 ellipsoid or ovoid narrowing into the stout persistent style. J. of B. xxi. 

 (1883) p. 353, t. 241. Upper internodes and backs of 1. often spinous. 

 Stigmas usually 3. Hickling .Broad and adjacent channels, Norf. A. 

 Vii. V11I. E. 



2. N. flex' His (Rostk.) ; [monoecious] 1. very narrow and very 

 minutely denticulate, sheaths ciliate-denticulate. Sy. E. B. 

 1432. L. ternate or opposite, 1-veined, pellucid, remotely den- 

 ticulate. [Anth. 1-locular.] Ovary solitary, axillary, sessile, 

 oblong. Style short. Deep lakes. A. VIII. 8. 1. 



\_N. minor (All.), monoecious, with narrow linear spinous-toothed recurved 

 falcate L, truncate sheaths, and 1-locular anth., occurs as a Pleistocene 

 fossil in Sussex and should be looked for. See J. of JB. xxxviii (1900) 

 p. 105, t. 408.] 



3. JV. gramin'ea (Delile) ; monoecious, st. branched throughout with 

 many simple lateral br., 1. tufted narrow linear with numerous minute 

 spinous teeth, sheaths toothed distinctly auricled, malefl. naked, anth. 

 1-locular, stigmas 2, tr. solitary or 2 4 together, narrowly ellipsoid. 

 J. ofB. xxii. (1884) p. 305, t. 250. Canal, Reddish, Lane., probably intro- 

 duced with Egyptian cotton. A. VII. IX. E. 



