994 BENGAL PLANTS. [Hydrilla. 
VI. MONOCOTYLEDONES. 
Sepals and petals usually similar, forming a generally 2-seriate, 
rarely 1-seriate perianth, rarely perianth 0. Stamens 1-2-seriate. 
Carpels usually connate. F'loral segments in each series usually 
8, sometimes 2, rarely 4 or more, or more rarely variously reduced. 
Embryo with one cotyledon. Herbs, rarely shrubs or trees, OF 
ith rhizomes produced in shrubby or arboreous stocks or culms; 
vascular bundles Beisel in the ground tissue. Leaves parallel- 
veined, the metimes united by transverse nerves; veins 
rarely aes or ah aR and reticulated. 
Order CXXY. HYDROCHARIDEZ. 
Aquatic, usually submerged herbs. Leaves radical, clustered ; 
auline, alternate pposi in ivided. Flowers 
Sepals 8, green or petaloid. Petals membranous or 0. ¢ Stamens 
—4-seriate; anthers 2-celled. ¢ Carpels connate in an 
inferior, 1-celled ovary ; hicaoneed 3-6, parietal or intruded, some 
es almost meeting in the axis; ovules numerous on each 
placenta, anatropous or orthotropous ; styles or style-arms 3-12. 
Fruit globose or ovoid, dry or pulpy, rarely Tebinen Seeds few 
or many; albumen 0; embryo smooth or lineate. 
Stems branching, leafy ; leaves small; spathes small, sessile 
— ves yee styles undivided ; ovules anatropous......--. " Hydrilla. 
s ...Lagarosi 
Stems none, or with stolons only, or a creeping rootstock :— 
Leaves all long and narrow, sessile ; male scapes several- flowered :— 
Perianth single Vallisneria 
Blyxa- 
led :-— 
Ovary beakless; fruit wingless; leaves all petioled ; male scapes 
1-flowered aris: 
entire or 2-leafed spathe; females solitary; perianth superior. 
. S 
several-fio y 
Ovary beaked; fruit winged; the submerged leaves narrow, the 
others long-petioled ; flowers solitary.........cccceeeeeceeeeeerett Ottelia. 
985. Hydrilla Rich. 
_A submerged, leafy herb; leaves short, usually opposite bees 
3-4-nately whorled above. Flowers dicecious; males short 
