1] : 
G Fibbon- likes > 2. Potamogetony (Tourn. )L. Pondweed. ? 
adkunedt ov thy upper opporte 
Aquatic plants with\flattened <-ranked leaves, either all similar, 
submerged and more or iess lineayfor some floating, dissimilar to the 
submerged ones, the blades dilateu and petioled; stipules membranous, 
more or less united and sheathing, enclosing the flower buds. Flowers in. 
axillary cylindrical spikes, usually emersed. ferianth segments 4, valvate ‘ 
in bud. Stamens 4, opposite the sepals} ovaries 4, distinct, l-chambered, forming 
4 sessile subglobose drupelets. 
QO Tlants with both floating and submerged leaves, the 
_f/former rather leathery and firm, the latter smaller, thin and limp 
f Naiffering in shape and texture y ERP E MALE 
A Floating leaves prevailingly shallowly cordate at the 
co submercsed leaves bladeless, consisting of 
’™\ petioles only, or wanting le fe natans 
2. Floating leaves narrowed at the base, never cordate; 
,) Submerged leaves with blades varying from linear 
6‘ to ovate : 
“ lLarcest submerged leaves 5-6 cm. broad Ce Es amplifolius 
/ Largest submerged leaves rarely 5 cm. broad, 
% usually less than & cm. 
f Submerged leaves narrowed to distinct 
1} petioles usually 5-5 cm. long or more 3 22 americanus 
? a ° . 
tf Submerged leaves sessile or sometimes 
} narrowed to indistinct retioles 
% Ploating leaves dull, narrowed at the base and 
jae. often attenuate into the petiole; stems 1-1.5 
~ - 7 s + 
‘mn. thick. 
tenuifolius 
[O submerged leaves similar in shape to the 
wy floating leaves but thinner, 8-15 mz. 
‘YS wide; plants tinged with reé ata 
{C Submerged leaves linear, dissimilar in 
shape to the floating leaves, infre- : 
l4{ quently 8 mm. wide, usually about 
4-5 mme; plants sreen 5e epi rus | 
% Ploatins leaves rather glossy, obtuse or 
_/ rounded at the base; stems and petioles very 
'¢{ slender, prevailingly .5 ma. in diameter or 
less Ge tek 
Q Fflants with ell leaves submerged, all similar 
7 Leaves ovate to lanceolate, 1.5-5 cm. wide ox more, 
Ciasring at the base, the margins wavy 
of 
4 Leaves blunt and lishtly hooded at the apex 
) Stipules persistent, very obtuse 7e + praelonsus 
i a 
a) 
we 
a al at ia gt satya = 22 
