NAIADACE^. 57 



of bracts. Filament at first short, afterwards Icnr^thening to a greater 

 or less extent; anthers 2- or 4-ceIled. Nuts 2 to 6 together, brownish- 

 olive, on a very short peduncle, subcylmdrical, incurved, i inch long 

 (including the beak) ; beak or persistent style about half the length of 

 the rest of the fruit; stigma Iai*ge, suborbicular, and slightly undu- 

 lated at the margins. Plant pale pellucid green, turning blackish in 

 drying. 



Reichenbach's figure of Z. major, " Bonningliausen," is the nearest 

 of those he gives to our common British plant, but is lai'ger than I 

 have ever seen it, and has the nuts much less spreading ; so I do not 

 venture to adopt his name for our sub-species, as Mr. Hartman 

 does. 



The form I found in Swanbister Loch, Orkney, is perhaps a distinct 

 sub-species; it has the beak ^ the length of the nut, which has a 

 scarious entire wing on the inner margins, and a broader crenulated 

 one on the back, but much narrower than in Z. pedicellata. The nuts 

 are divaricate, so it is not Z. polycai^^a, Nolte 



Common Horned Ponclweed. 



French, Zannichelle des marais. German, Kurzgestielte Zannicliellie. 



Sdb-Species (?) n. — Zannichellia pedicellata. Fries. 



Plate MCCCCXXVI. 



Eeicli. Ic. Fl. Gei-m. et Helv. Vol. VH. Tab. XVI. Fig. 21. 

 C. pedunculata, Reich. 1. c. p. 22. 



Nuts distinctly pedicellate, spreading, with a winged crenulate- 

 dentate keel on the back ; beak as long as the rest of the fruit. 



In brackish ditches. Frequent in England, and probably m Ireland, 

 as it is said to grow near the sea. I have seen no Scotch specimens. 



England, Ireland. Annual or Peremiial. Summer, Autumn. 



Similar to the preceding, but usually larger and more branched. The 

 nuts are larger, paler coloured, on conspicuous pedicels, and with a much 

 longer beak; the upper or inner margin with a very narrow entire 

 wing or raised line, the back with a broad membranous wing decurrent 

 on the pedicfd, and denticulated, with a tubercle or point given otF 

 from the body of the nut running mto each denticulation. The pe- 

 dicels are commonly about two-thirds the length of the nut, and as 

 long as the common peduncle. 



1 cannot find that the length of the stamens and the number of cells 

 of the anthers are sufficiently constant to warrant their employment 

 as specific characters, as proposed by M. Gay. 



Stalked-fruited Horned Po7idweed. 

 French, Zannichelle pedonculee. GermaD, LoM'jjestieUe ZannichelUe. 

 VOL. IX. I 



