512 MANUAL OF NATUKAL HISTORY. 



finite, sessile, 1-2-celled ; pollen confervoid ; 

 ovary free, 1 -celled ; ovule solitary ; stigmas 

 1-2 ; fruit drupaceous, 1-seeded ; seed pen- 

 dulous. Marine plants, inhabiting the bottom 

 of the ocean, principally in Northern parts of 

 the Eastern Hemisphere. 



2. Family. — Pond-weeds (Naiadaceae). Leaves very 



cellular, stipulate ; flowers inconspicuous, 

 often in terminal spikes ; perianth of 2-4- 

 pieces, deciduous, sometimes ; stamens de- 

 finite, hypogynous ; pollen globose ; ovaries 

 one or more, superior] ovule solitary; stigma 

 simple ; fruit dry, 1-celled, 1-seeded ; seed 

 erect or pendulous. Natives of extra-tropical 

 countries in fresh- water, or on the sea-shores. 

 (Potamece, Juss.) 



3. Family. — Frog bits (Hydrocharidacese). Herbs ; 



leaves sometimes spiny; flowers spathaceous, 

 occasionally bisexual ; perianth with a 6-par- 

 tite limb, the outer herbaceous, the inner 

 petaloid ; stamens definite or indefinite, 

 epigynous ; ovary adherent, 1- or many- 

 celled j stigmas 3-6; ovules 00; fruit dry 

 or succulent, indehiscent, 1- or many-celled. 

 Fresh- water plants, inhabiting Europe, North 

 America, and India. 



II. ORDER— Palmals (Palmales). 



Flowers perfect, on a branched, scaly spadix ; 

 embryo minute, placed beneath the surface of horny 

 or fleshy albumen ; unisexual or bisexual. 



