FAMILY KEY 



A. GYMNOSPERMS (CONE BEARERS) Trees or shrubs, evergreen (except Larix), 

 cone-bearers (except Taxus and Juniperus) ; leaves either needles or scales ; 

 ovules not inclosed in an ovary. 



B. Fruit a red berry; leaves complanate, scattered, needle-like, flat, sharply 

 acute or acuminate ; ovule i ; flowers dioecious, solitary, axillary. 



TAXACEAE (p. 29) 



BB. Fruit either a woody cone or a bluish berry ; leaves not agreeing with the 

 above in all points ; ovules 2 to several on each scale ; flowers mostly monoecious, 

 mostly several grouped together forming cones ; cones usually axillary. 



PINACEAE (p. 29) 



AA. ANGIOSPERMS (OVARY PLANTS) Trees or shrubs or herbs, mostly not 

 evergreen ; inflorescence rarely conelike ; leaves rarely needles or scales ; ovules 

 inclosed in an ovary. 



C. MONOCOTYLEDONS Herbs or one a vining shrub (Smilax), some leafless and 

 floating ; leaves parallel-veined, or the chief veins from the base, or i-veined, or 

 none ; flower parts in 3's, rarely in 4*3, never in 5*3 ; wood usually in bundles 

 scattered throughout the stem; cotyledon i. 



D. Plants free-floating; body thalloid, without a distinct stem or leaf; roots 



unbranched or none. LEMNACEAE (p. 51) 



DD. Plants not free-floating, or if so having leaves ; leaves usually present ; stem 



present or the leaves tufted at base ; roots present, usually branched. 



E. Leaves narrow, linear or grasslike. GROUP i (p. 7) 



EE. Leaves none, or mere scales, or at least some of them too wide to be linear. 



GROUP 2 (p. 9) 



CC. DICOTYLEDONS Herbs or shrubs or trees, never leafless when floating; 

 leaves netted-veined, or the chief veins from the base, or i-veined, or none; 

 flower parts rarely in 3's, mostly in 4*3 or s's ; wood usually in a circle or in 

 several concentric circles about a central pith; cotyledons 2. 



KEY TO THE DICOTYLEDONS (p. 10) 



GROUP 1 Monocotyledons with narrow leaves 



A. Plants growing in salt water near the low-tide line, submerged in the sea; 



leaves 3-20 dm. long, flat or folded lengthwise. NAIADACEAE (p. 34) 



AA. Plants not growing near the low-tide line of the sea, although sometimes 



growing along seashores ; leaves often not as above. 



B. Plants submerged in fresh or saline waters; leaves opposite or whorled, not over 



5 mm. wide. 

 C. Leaves toothed at margin, 0.4-2 mm. wide, 8-25 mm. long. 



Naias in NAIADACEAE (p. 34) 

 7 



