472 HYDROCHARITACEE. { Hype. 
entire or 2-leaved spathe ; Mare flowers: stamens 3-12, in 1-4 
series, anthers 2-celled. Frm. flowers: Solitary. Pertanth 
superior. Sepals 3, green or petaloid. Petals membranous or 
none. Ovary 1-celled, inferior ; placentas 3-6, parietal or intruded) 
and sometimes almost meeting at the axis; styles or style-arms. 
3-12; ovules many oneach placenta, anatropous or orthotropous. 
Fruit globose or ovoid, dry or pulpy, rarely dehiscent. Seeds 
few or many, albumen none, embryo smooth or lineate—Species: 
about 50, in tropical and temperate regions of the world, some of 
them marine. 
Stems branching, leafy; leaves small; spathes 
‘small, sessile :— 
Leaves whorled or the lower ones opposite ; 
styles undivided ; ovules anatropous . lL. Hydrilla. 
Leaves scattered, fascicled or somewhat whorl- 
ed ; styles notched ; ovules orthotropous . 2. Lugarosiphon.. 
Stems none, or with stolons only, or a creeping 
rootstock :— 
Leaves all long, narrow and sessile; male 
scapes several-fid. :— 
Perianth single ; ; ‘ : . 3. Vallisneria. 
Perianth double ; : : . 4. Blyzxa. 
Leaves mostly or all petioled :— 
Ovary not beaked; fruit without wings; 
leaves all petioled ; male scapes 2-3-fld. . 5. Hydrocharis. 
Ovary beaked; fruit winged, submerged ; 
leaves narrow, the floating ones long- 
petioled ; flowers solitary : Me . 6. Oltelia. 
1, HYDRILLA, Rich. ; Fl. Brit. Ind. v, 659. 
A submerged leafy freshwater herb. Leaves short, usually 
opposite below, 3-4-nately whorled above. Flowers minute,. 
dicecious, the males shortly pedicelled, solitary in a subglobose 
muricate spathe ; females sessile, 1-2 in a tubular 2-toothed spathe. 
Matz flowers : Sepals 3, ovate or obovate, green. Petals 3, oblong 
or cuneiform. Stamens 3; anthers large, reniform, opening elasti- 
cally. Pisitllode minute. Frm. flowers: Sepals 3, linesr, green,. 
