224 COMMON CANADIAN WILD PLANTS. 



9. NAI'AS, L. Naiad. 

 N. flex'ilis, Rostk. and Schmidt. Stems very slender. 

 Leaves very narrowly linear, minutely serrulate. 



3. ZANNICIIEIiaiA, Micheli. Horned Pondweed. 



Z. palus'tris, L. Fruit obliquely oblong, flattish and 

 somewhat incurved. Style half as long as the nutlet. 



4. aoSTE'RA, L. Eel-grass. Grabs-wrack. 



Z. mari'na, L. Leaves obscurely 3-5-nerved. — Atl. sea- 

 coast, in shoal water. 



II. PBTALOI'DEOUS DIVISION. 



Flowers with a perianth coloured like a corolla. 



Order XCVIII. ALISMA'CEiE. (Water Plantaik F.) 



Mar.sh herbs, with flowers having 3 distinct sepals and 

 3 distinct petals, pistils either apocarpous or separating at 

 maturity into distinct carpels, and hypogynous stamens 6- 

 niany. Flowers on scapes or scape-like stems. Leaves 

 sheathing at the base either rush-like or, when broad, mostly 

 heart-shaped or arrow-shaped. 



Synopsis of the Clenera. 



''Calyx anil corolla both greenish. Carpels -more or less united^ but 



spreading at maturity. Leaves rush-like and fieshy, or 



grass-like. 



1. Trtglo'clilii. Flowers small, in a spike or close raceme, without 



bracts. Carpels united to the top; when ripe, splitting awaylrom 

 a central persistent axis. 



2. Sfheuchze'ria. Alow bog-herb, with a creeping jointed rootstock, 



and grass-like leaves. Stamens 6. Carpels 3, globular, nearly 

 distijict. 

 (Tlicse two genera are included in Naiadacese in Macoun's Catalogue.) 



**Calyx green, persistent. Corolla white. Pistil apocarpous. Leaves, 

 with distinct blades and petioles. 



3. Alls'nia. Flowers perfect. Stamens usually 6. Carpels numerous 



in a ring. Leaves all radical. Scapes laith whorled panicled 

 branches. 



