6 BIOLOGICAL CLASSIFICATION [CH. 



(ii) Plants in which the floating type of leaf is generally 

 associated with the flowering stage. 



E.g., Nymphaea lutea^ L. (Yellow Waterlily). 

 Castalia alba y Greene (White Waterlily). 

 Various Batrachian Ranunculi (Water Butter- 

 cups). 



Callitriche verna, L. (Water Starwort). 

 Potamogeton natans^ L. (Pondweed). 



D. Plants which may, in certain cases, occur as land forms, 

 but are normally submerged and are characterised by a creep- 

 ing axis bearing long, branching, leafy shoots with no floating 

 leaves, or by a plexus of leafy, rooting shoots without a creeping 

 rhizome. 



(i) Leafy aerial shoots produced at the flowering period. 

 E.g., Myriophyllum verticillatum, L. (Water Mil- 

 foil). 

 Hippuris vulgaris, L. (Mare's-tail). 



(ii) Inflorescence raised out of the water, but no aerial 

 foliage leaves except in the land forms. 



E.g., J^yriophyllum (except M. verticillatum) (Water 



Milfoil). 



Hottonia palustris, L. (Water Violet). 

 Many Potamogetons (Pondweeds). 



(iii) Inflorescence submerged, but essential organs raised 

 to the surface. 



E.g., Elodea canadensis^ Michx. (Water Thyme). 



(iv) Inflorescence entirely submerged and pollination 

 hydrophilous. 

 E.g., Naias. 



Zannichellia (Horned Pondweed). 



Zostera (Grass- wrack). 



Callitriche autumnalis^ L. (Water Starwort). 



Halophila. 



