444 
96. NAIADACE^. 
2. Rup'piA Linn. Tassel-Pondweed. 
1. R. 7narit'iina (L. em., Koch) : ped. long spiralli/ tivisted, 
anth.- cells oblong lA times as long as broad, nut ovoid rather 
obliquely erect. — E. B. 136. R. vii. 17. R. spiralis Hartm. — 
Whole plant stronger than the next. L. very narrowly linear, 
formed as in Potainorteton pectinatus. Sheaths large, inflated. 
—Salt marshes. P. VII. VIII. E. S. I. 
2. R. rostelldta (Koch) ; ped. short not spiral, anth. -cells 
squarish as long as broad, nut gibbous at base obliquely ascend- 
ing when young. — Sy. E. B. 1-128. R. vii. 17. — Whole plant 
very slender. L. rather filiform than linear. Sheaths small, 
close. — A very small form {nana Bosw.), with very short de- 
curved ped., is found in Orkney. Salt marshes. P. VI. — VIII. 
E. S. I. 
3. Zannichel lia Linn. Horned Pondweed. 
1. Z. palus'tris (L.) ; style at least half as long as the diver- 
gent nuts. — E. B. 1844. — Floating. L. slender, opposite, fili- 
form. Fl. axillary, sessile. — a. hrachysfenion (Gay) " ; Jr. 
2 — 4 S2(bsessile with crenate back, style ^ length of fr., stigma 
large crenulate, anth. 2-celled. — j3. "Z. macrostemon (Gay) " ; 
fr. 2 — 4 sessile rarely crenate, styled length of fr., stigma small 
crenulate, anth. 4-celled. — y. pedicellata (Wahl. et Rosen.) ; 
fr. 2 — 5 stalked' muricate, style as long as fr.. stigma large 
crenulate, anth. 2-celled. S)/. E. B. 1426. Z. pedvnculata 
(Reich.). Z. pedicellata (Fr.). — I doubt the constancy of these 
characters. — Stagnant water, y. Brackish water. A. or P. 
v.— VIII. E. S. I. 
2. Z. polycar'pa (Nolte) ; style scarcely of length of con- 
verging sessile nuts,/r. 5 — 6'subsessile crenulate on back, con- 
verging, style scarcely I length o//r., stigma large repand, anth. 
2-celled. — Much like Sp. 1. — In water. Orknev.' Belfast. 
A. V. -VIII. ' S. I. 
Order XCVI. NAIADACE^. 
Fl. monoecious or dioecious, in a spath. Perianth 0. Stam. 
free, 1 — 3. Ovary 1, superior, with 1 ovule. Style 1 ; stigmas 
2 — 4, filiform. Fr. a nut enclosed in the persistent spath, 
1-celled, 1-seeded, not bursting. Albumen 0. Embryo with a 
thin skin having a lateral cleft. 
1 Dr BoswbU referred the Orkney plant, with longer styles and less conniveiit 
fr., to var. tenuifsimu (Fr.). — H. & J. G. 
