64 MISSOURI BOTANICAL GARDEN BULLETIN 
feet. The plant is quite attractive, but is a rather poor 
oxygen generator, 
Eel-grass (Vallisneria spiralis) —A grass-like plant native 
of North America, with strap-shaped leaves varying from one 
to three feet in length, light green in color, and translucent. 
The sor 
the base of the 
spiral, submerging the flower for fertilization. 
, floating pistillate flowers are connected to 
plant by a long filament which later becomes 
The stami- 
nate flowers are globular, produced at the base of the plant, 
from which they break away, rising to the surface of the 
water. They float with the stream, pollen exposed, so that 
when contact occurs with the pistillate flowers, pollination 
readily takes place. This plant is a very good oxygen gen- 
erator. 
Water-weed (Elodea canadensis var. gigantea) —Native of 
North America, moss-like in growth. The leaves are in 
whorls upon light green stems which form strands reaching 
several feet in length. This is an excellent oxygen gener- 
ator, growing completely submerged. It may become a 
pestiferous weed in lily ponds. 
Ribbon arrowhead (Sagittaria subulata) —Native of 
North America. The submerged leaves are equitant, strap- 
shaped, dark green, one foot in length. The growth above 
water bears lance or sagittate leaves. This plant is one of © 
the most valuable for aquarium purposes, multiplying rap- 
idly by stoloniferous growths and supplying a plentiful 
amount of oxygen. A very noxious weed in ponds. 
_PLANTS SUITABLE FOR AQUARIA 
Botanical name Common name Habit 
Aponogeton distachyus... -Cape pond-weed Floating 
Aponogeton fenestralis... .Lace-leaf Submerged 
Azolla caroliniana......., Water moss Floating 
Cabomba caroliniana ..... Fish-grass Submerged 
Callitriche verna ........ Spring starwort cubmerged or 
oating 
Ceratopteris. thalictroides..Water fern Leaves floating 
or above water 
Oryptocoryne Griffithii ...Mosaic leaf Submerged 
Oyperus alternifolius var. 
variegatus ............ Variegated Leaves above 
umbrella plant water 
Cyperus Papyrus ........ Egyptian pepper Leaves above 
plant water 
Eichhornia speciosa ...... Water hyacinth Floating 
Elodea (Anacharis) can- 
ne ey, OE ERE As Water-weed Submerged 
Eriocaulon septangulare ..Hair grass Submerged or 
above water 
Habitat 
South Africa 
Madagascar 
North America 
North America 
North America 
Tropics 
Malaya 
Madagascar 
Egypt 
Southern United 
States 
North America 
Southern United 
States 
