53G NAiADACE^. [linppia. 



briglit Rieen, aUernate, very finely linear, setaceous or almost capillary, which they 

 very soon become on exposure to the air, in the specimens before me appearinfc 

 under a high magnifier rounded or nearly terete, not flat, move or less grooved 

 above, very indistinctly single-nerved from the shining through of a central chord, 

 transversely reliculated, springing from long close sheaths, that embrace the stem, 

 are somewhat open at bottom, lined with the stipule, which projects beyond it into 

 a pointed scarious appendage, analogous to the ligule in grasses, and which falls 

 away for the most part. Spikes solitary, axillary or terminal, on terete simple 

 peduncles, of various, mostly very great, length, more or less interrupted. Flowers 

 large, sessile, in pairs opposite to each other or 3 together. Segments of Ihe peri- 

 anth rounded, entire, concave. Anthers large, of 2 white oblong lobes diverging 

 below, bursting at the back. Nuts pale greenish or grayish brown, one or two 

 sometimes abortive, roundly ovate or obovate, subcompressed, slightly and subtu- 

 berculately rugose and shining, the short broad apex a little oblique, in my fresh 

 specimens without a keel or any lateral ridges. 



***** Leaves all opposite and submersed. Stipules none. 



7. 1?. densus, L. Close Opposite-leaved Pondweed. "Leaves 

 crowded all opposite pellucid amplexicaul ovato-acuminate or lan- 

 ceolate, spikes shortly stalked about d-flowered finally refiexed." 

 —Br. Fl. p. 466. E. B. i. 397. 



In ditches and pools. Fl. June, July. If. 



E. Med. — Marsh-ditches at Sandown. [Brading marshes, A. G. More, Esq., 

 Edrs.] 



W. Med. — Ditches in the marsh at Freshwater gate, abundantly. 



Well distinguished by its narrow opposite leaves and the absence of stipules. 



II. KuppiA, Linn. Tassel Pondweed. 



" Floivers perfect, about 2 on a spike (or spadix ?) arising from 

 the sheathing bases of the leaves, which perform the office of a 

 spatha. Perianth 0. Stamens 4. Anthers 1-celled. Style and 

 stigmas undivided. Achenes 4, on long stalks, 1-seeded. Albu- 

 men 0." — Br. Fl. 



1. R. maritima, L. Tassel Pondiveed. Sea Tassel-grass. E. 

 B. t. 136. Fl. Lond. t. 50. Br. Fl. p. 471. 



In ditches and pools of salt water ; very commonly, i^/. July, August. If. 



F. Med. — Ditches at the back of the Dover, Ryde. Ditches between Spring- 

 field and Old Fort. 



W. Med. — Salt-water ditches about Yarmouth and Freshwater, plentifully. 

 Ditches in the salt-marsh near Yarmouth, in the greatest abundance, Mr. Snoohe. 

 [/3. rostellata. Abundant near the sluice at Brading, A. G. More, Esq., Edrs.] 



III. Zanichellia, Linn. Horned Pondweed. 



" FZowers monoecious. — Barren flowers : — Perianth 0. Stamen 

 1. Anthers 2 — 4 celled. — Fertile floivers : — Pmani/i single, of 1 

 leaf. Germens 4 or more. Styles undivided. Stigma peltate. 

 Achenes nearly sessile." — Br. Fl. 



1. Z. palustris, L. Horned Pondweed. E.B. t. 1844. Br. 

 Fl. p. 472. 



In salt- and fresh-water ponds and ditches, in various places. Fl. July, Au- 

 gust. 0. 

 E. Med. — Ditches on the Dover marsh, plentiful. Ditches between Springfield 



