Vm ANALYTIC KEY TO THE FAMILIES 



A. Small, elliptical or flask shaped, aquatic plants without true stems 



or leaves, and swimming freely on the water . Lemnaceos, p. 14 

 AA. Plants with true stems and leaves, the latter sometimes reduced to 

 scales. 

 B. Perianth free from the ovary or wanting.. 

 n. Perianth wanting or scale-like. 

 D. Flowers enclosed in husk-like scales (glumes) ; grass-like 

 plants With jointed stems, sheathitig leaves and 

 1 -seeded fruit. 

 Stems hollow ; leaf-sheaths split . . Oraminew, p. 10 

 Stems generally solid, often triangular ; leaf-sheaths 



not split Cyperaceoe, p. 13 



DD. Flowers not enclosed in glumes. 



Rush-like marsh plants with an ovary of 3 carpels 



Juncacew, p. 14 

 Leafy immersed plants with perfect flowers 



NajadacecB, p. 8 

 Flag-like marsh plants with flowers in dense cylin- 

 drical spikes Typhaceoe, p. 7 



cc. Perianth always present, either colored or herbaceous but 

 never scale-like. 

 j!i. Pistils numerous in a head or ring . Alismacew, p. 9 

 EB. Pistil one ; compound. 



Stamens 3 ; marsh hel-bs with rush-like leaves and 



flowers in spikes .... Juncaginaceoe, p. 8 



Stamens 4 mianthemum, p. 17 



Stamens 6 ; 



Divisions of the perianth alike. 



Rush-like plants Juncacece, p. 14 



Not rush-like lAliacece, p. 15 



Divisions of the perianth not alike ; leaves net- 

 veined TRILLIUM, p. 19 



BB. Perianth adhering to the ovary. 



Immersed aquatic herbs HydrochariiacecB, p. 9 



Terrestrial herbs. 



Stamens 2 ; flowers irregular Orchidacem, p. 22 



Stamens 3 '. . . . . Iridacem, p. 21 



Stamens 6 Amaryllidacece, p. 21 



Class 2. DICOTYLEDONE^ 



stems with a central pith ; if woody, the wood arranged in annual 

 rings ; leaves net-veined ; embryo with two cotyledons. 

 A. Corolla absent. 



B. Flowers monoecious or dioecious ; one or both kinds in catkins or 

 catkin-like clusters. 



