131. HYDROCHARITACEM. 



FAM. 131. HYDROCHARITACE^. 



Aquatic herbs with simple undivided leaves with 1 to many basal 

 nerves. Flowers minute to showy, monoecious or dioecious, enclosed 

 in a spathe, female solitary. Sepals 3, green or petaloid. Petals 

 membranous or 0. Stamens 3-12, anthers 2-celled. Ovary inferior, 

 placentae parietal or almost meeting in axis, styles or stigmas 3-12, 

 Ovules anatropous or orthotropous. Fruit membranous or fleshy, 

 rarely dehiscent. Seeds few to many, exalbuminous. Embryo 

 various. 



I. Stem branched leafy. Spathes short sessile :— 



Leaves whorled. Perianth double. Ovules anatropous . I. Hydrilla. 

 Leaves alt. Perianth single. Ovules orthotropous . . 2, Lagarosiphon. 

 11. Stemless or with stolons bearing sessile tufts of leaves or 

 with creeping rootstock : — 



A. Leaves gi-ass-like without distinct petiole, spathes on long 



radical verj' slender peduncles : — 



Perianth single. Fls. 1-sexual 3. Vallisneria. 



Perianth double. Fls. 1-2-sexual 4. Blyxa. 



B. Leaves broad, petioled. Spathes peduncled : — 



Tufts of leaves floating. Male spathes 2-3-fld. Ovarj- 



not beaked 5. Hydrocharh. 



Rooting at the bottom. Leaves submerged and floating. 



Spathes 1-fld. Ovary beaked .6. Ottelia. 



1. HYDRILLA, Riclwrd. 



Submerged, leafy, dioecious or monoecious, M'ith short whorled 

 leaves or the loAver opposite. Male fl. solitary, shortlj' pedicelled, in 

 a subglobose sessile muricate spathe, sepals 3, ovate or obovate, 

 green ; petals 3 oblong or cuneiform ; stamens 3, anthers large reni- 

 form, opening elastically, pollen large white firm, pistillode small. 

 Fem. fl. 1-2. sessile in a tubular 2-toothed spathe ; hypanthium 

 produced into a long filiform neck above the ovary, perianth as in 

 male but the segments narrower ; ovary 1 -celled, styles 2-3 linear, 

 stigmas fimbriate. Ovules anatropous. Fruit subulate, smooth or 

 muricate. Seeds 2-3 oblong, testa shortly produced each end. 



1. H. verticillata, Casp. 



A weak water-herb having a general appearance of Elodea cana- 

 densis and, like it, forming large masses suspended beneath the surface. 

 Stems slender branched with linear or shortly-linear, usually spinu- 

 losely -serrulate, leaves -25- -4", rarely -5" long, 4-8 in a whorl, spread- 

 ing Avith recurved tips. 



In tanks and slow-running streams. No doubt in all districts. In the Ganges 

 at Monghyr, Lockwoodl Behar. Kew Herb.l Singbhum ! Cuttack, canals! 

 Raneeganj, Kio-z ! Chilka Lake, Cal. Herb. ! Fl. July-Sept. 



L. rarely 'o" and narrow-elliptic. M.fl. in whorls sessile at the base of each leaf, 

 escaping from the muricate spathe when mature and swimming on the surface. 

 Fem. above the males if monoecious or in separate terminal branchlets (Clarke) 

 and usually solitary in the whorl or opposite. Stigmas pink. 



2. LAGAROSIPHON, Harv. 



Submerged, dioecious, with alternate leaves or sometimes leaves 

 fascicled or subverticillate and lower opposite, serrulate. Male fls. 



852 



