Potamogeton. | NAIADACE. 749 
minute areolation; stipules very long and conspicuous, 3-din., 
free, acuminate. Submerged leaves wanting or if present few and 
reduced to long and narrow phyllodes without any lamina. Pe- 
duncles stout, 2-4in. long, bearing a dense-flowered spike 14-2 in. 
long. Perianth-segments broadly rhomboidal. Fruit 4in. long, 
turgid, obliquely ovoid, keeled on the back when dry, beak short.— 
Hook. f. Fl. Nov. Zeal. i. 236; Handb. N.Z. Fl. 278; Benth. Fl. 
a as vii. 170 (im part); A. Bennett in Journ. Bot. xxv. (1887) 
vith 
NortH Aanp SoutH Istanps: Probably not uncommon. 
A widely dispersed plant, found in nearly all temperate climates. Its exact 
distribution in New Zealand is not yet made out with certainty, as P. Cheese- 
mani has been recorded in mistake for it in many localities, but I have seen 
specimens from both Islands. 
2. P. polygonifolius, Powrr. in Mem. Acad. Toul. in. (1788) 
325.—Stem creeping at the base, long or short, simple or sparingly 
branched. Floating leaves on long petioles; lamina 1-3in. long, 
elliptic-oblong to lanceolate, acute or obtuse, rounded or subcordate 
or acute at the base, not plicate, thinly coriaceous; stipules much 
shorter than in P. natans, 1-14in. long. Submerged leaves 
linear-lanceolate, acute. Peduncles variable in length, rather 
slender; spike dense-flowered, #-14in. long. Perianth-segments 
transversely elliptic. Fruit small, reddish, j4-;,in. long, blunt 
and rounded on the back, not keeled, beak very short.—Kirk in 
Trans. N.Z. Inst. ii. (1871) 165. 
NortH AnD SoutH Istanps, STEWART IsuAND: Ponds and small streams 
from the North Cape southwards, not uncommon. Sea-level to 1500 ft. 
December—April. 
Distinguished from P. natans by the smaller and more membranous 
leaves, much shorter stipules, slender peduncles, and much smaller fruit not 
keeled on the back when dry. Several of my specimens have been examined by 
Mr. A. Bennett, of Croydon, whose knowledge of the genus is unrivalled, and 
he informs me that their identity with P. polygonifolius cannot be questioned: 
The species is widely spread in Europe and Asia, and has been recorded from 
Australia. 
3. P. Cheesemanii, A. Bennett in Journ. Bot. xxi. (1883) 66.— 
Stems slender, striated, long or short, simple or branched. Upper 
leaves alternate or opposite, long-petioled; lamina #-1#in. long, 
elliptic-oblong to oblong or lanceolate, obtuse, rounded at the base, 
coriaceous, 10-16-nerved with numerous cross-veins and minute 
areolation ; stipules broad, subacute. Submerged leaves numerous, 
usually alternate but sometimes opposite. shortly petioled, 2—-41in. 
long, 4-2in. broad, oblong-lanceolate to lanceolate or linear, very 
thin and membranous, translucent, 5-12-nerved with rather dis- 
tant cross-veins, margins often undulate or crisped, not denticulate. 
Peduncles variable in length, rather slender; spike dense, 4—}in. 
