or of membranous or chaffy scales, not at all 
petal-like and showy, but inconspicous; rush- 
( like or grass-like plants, commonly inhabitants 
of bogs or growing in water; flowers commonly 
in dense spikes or globose headsy 
@ Z &a.Perianth either none or consisting of bristles 
4 small tufted plants with linear leaves 2 cm. Pom 
(tor or less, wholly submerged in water, the ~ ™ | a 
ji 
flower minute, inconspicuous, axillary, A 
Naiadacese (0+). 
cura)? \consisting ofa single stamen or a single pistil 
ro HLS 
: va er Pg 
4 Plants not as described above ; Ne eS a cee Sy 
—— —r 
( Rush-like plants as tall as a man,with 
linear leaves and flowers borne in compact 
: terminal cylindrical spikes 12-15 cm. long, 
io the staminate spike immediately above the 
“\ pistillate spike; perianth of hairlike e 
vristles,x Typhaceae (6.—)} 
A Plants not as described above d 
8 Partly submerged, often partly floating, 
rush=like plants with flowers borne in 
|z, (several axillary spherical heads; per- 4 
ianth of chaffy scales Sparzaniaceae (. 
8 Plants not @s described avove 
JO Plants rooting in bottoms of streams, 
lakes or pools, the stems mostly sub- 
merged, the upper leaves sometimes 
oval and flat, floating on the sur- 
face, sometimes all linear and sub- 
merged; flowers either in dense spikes 
14 the diameter of a small lead pencil or 
less, one to several centimeters long, 
elevated above the surface of the 
water or 2lse in small axillary clustersy .—__ ss >. 
- Potamogetonaceae 
. _— 
, 
JO Plants not asdabove; erect terrestrial  _ _ 4 
plants growing often in bogs or marshes, : oF 
/4 (varsly in wate:'y/ ; 
/2%,Plants. with large fleshy leaves 
20-100 em. long; flowers borne in a 
t scupact cylindrical spixe which is 
