42 FLORA OF TASMANIA. | Alismacee. 
My specimens are not satisfactory, having only young flowers, and few floating leaves ; it may prove to be a 
variety of P. natans. This character 1 have adopted from the British Flora, the Tasmanian plant agreeing with it, and 
with European specimens.—Floating leaves like those of P. natans, but narrower and more membranous ; submerged 
ones numerous, narrow lanceolate, stalked, membranous, entire, toothed, or erisped. Pedunele short, thickened 
upwards.—Some Tasmanian specimens have rigid, wiry stems, and all the leaves lanceolate, opaque, and coriaceous. 
This is possibly P. erispus of Mr. Brown, from Port Jackson, who has added to the specific name “non Linn.” in 
my copy of his “Prodromus.” Koch refers P. heterophyllus, Schreb., to a variety of gramineus, which this plant 
may be. 
3. Potamogeton gramineus (Linn. Sp. Pl. 184); foliis omnibus submersis linearibus obtusis 
membranaceis trinervibus, venis transversis paucis remotis, pedunculo brevi spica sepius vix longiore.— Bv. 
Prodr. 948; Engl. Bot. t. 2958. 
Has. South Esk River (growing with P. natans), Guan. 
Distri. Europe, India, and various other parts of the world, as Australia and New Zealand. 
A very different-looking and greener plant than the two fo 
rmer.—S/ems elongated; branches long, simple. 
Leaves 2—4 inches long, 2 inch broad, linear, blunt, with three parallel veins connected by a few distant transverse 
ones. Peduncles short, as are the spikes. 
Gen. III. RUPPIA, Z. 
Flores hermaphroditi v. unisexuales, spicati, pauci. Perianthium 0. Stamina 2-4, interdum dissita ; 
filamentis brevissimis, squameformibus; antheris magnis, extrorsis, polline trihedro. Ovaria 4, sessilia, 
demum stipitata, 1-locularia ; ovulo 1, pendulo; stigmate sessili, peltato. Fructus e carpellis 1-4 longe sti- 
pitatis indehiscentibus, gibbosis; semen pendulum, exalbuminosum, uncinatum, cruribus inzequalibus. 
Embryo homotropus, macropodus, cotyledone acuminata.— Herbze gracillime, 
habitantes; ramis filiformibus ; foliis lineari-setaceis, filiformibus, 
À very widely-distributed plant, forming matted masses of long, very narrow, slender, greenish-brown stems 
and foliage, in brackish water.— Stems very slender, 6 inches to several feet long. Leaves alternate, sheathing be- 
low, very long, narrow, and linear. Flowers in the axils of the leaves. Spadiz much lengthened after flowering, 
and spirally twisted (as in Vallisneria). Ovaries sessile. Peduncles of the fruit much lengthened, often an inch 
long. Nuts very small, oblique, compressed, with sharp or blunt styles.—An extremely variable plant in Europe, 
of which several species have been made on insufficient grounds. (Named in honour of Henry Barnard Ruppius, 
an early German botanist.) 
l. Ruppia maritima (Linn. Sp. Pl. 184).—F7. N. Zeal. i. 236. 
Haz. Fresh and brackish water near the 
(v. v.) 
Disrris. Europe and North Africa, Red Sea, peninsula of India, 
Sandwich Islands, east and west coasts of North America, West Indies 
cespitose, aquam salsam 
basi vaginantibus. 
(Gunn, 1359, 1359 P.) 
sea; abundant in the Derwent, Tamar, etc.— (Fl. Oct.) 
and Ceylon, Australia, New Zealand, 
Gen. IV. ZANNICHELLIA, Z. 
Flores monoici. Masc. Stamen 1, s 
longa, 2—4-locularis ; pollen globosum. pedicellata, 1-locularia, 1- 
sperma; stylo recto ; stigmate dilatato ; » pendulo, orthotropo. Nueule 4, breve pedicellatze v. ses- 
siles. Semen pendulum, exalbuminosum : 
; testa tenui; cotyledone elongata, circinatim inflexa; radicula 
macropoda.—Herbe natantes, tenella, aque dulcis. 
