xxiii 



GROUP 2 } UNUSUAL PLANTS 



la. Small brown leafless plants, growing as parasites on the tamarack 

 or black spruce LORANTHACEAE, p. 25. 



Ib. Aquatic plants, with all or most of the leaves submerged, or leaf- 

 less 2. 



Ic. Aquatic plants, with the leaves or the whole plant floating on or 

 near the surface 20. 



Id. Terrestrial or marsh plants, without floating or submerged leaves 

 29. 



2a. Submerged aquatics, without leaves 3. 



2b. Submerged aquatics, with the leaves linear or dissected 4. 



3a. Flowers showy, yellow or purple LENTIBULARIACEAE, p. 105. 

 3b. Flowers small and inconspicuous, sessile, purplish or greenish 



3a, in HALORAGIDACEAE, p. 79. 



4a. Leaves linear or lanceolate, not lobed or dissected 5. 

 4b. Leaves more or less lobed or dissected 13. 



5a. Leaves all basal 6. 

 5b. Stem-leaves present 7. 



6a. Flowers blue, 1 cm. long or more; leaves cylindrical, blunt, 



hollow, partitioned lengthwise la, in LOBELIACEAE, p. 113. 



6b. Flowers yellow; leaves minute LENTIBULARIACEAE, p. 105. 



6c. Flowers white, in clusters; leaves linear-lanceolate, acute, 



not hollow Ib, in ALISMACEAE, p. 3. 



6d. Flowers greenish, solitary at the end of elongated peduncles; 



leaves very long and ribbon-like, flat or trough-shape 



la, in HYDROCHARITACEAE, p. 3. 

 6e. Flowers minute, whitish or lead-color, in heads 



ERIOCAULACEAE, p. 9. 

 7a. Leaves alternate 8. 

 7b. Leaves opposite 10. 

 7c. Leaves whorled 12. 



8a. Leaves with thin sheathing stipules 



Ib, in NAJADACEAE, p. 2. 



8b. Leaves without stipules 9. 



9a. Flowers greenish, in a head SPARGANIACEAE, p. 2. 



9b. Flowers pale yellow Ib, in PONTEDERIACEAE, p. 10. 



lOa. Leaves serrate 2b, in NAJADACEAE, p. 2. 



lOb. Leaves entire 11. 



