1 8 KEY TO THE FAMILIES 



Ovary or ovaries simple; flowers with only scale-like 

 calyx, if any, and no corolla. 

 Flowers not in axils of dry chaffy bracts. 



a. Immersed branching aquatics with thread-like 



leaves, or the floating leaves broad and flat. 



Naiadaceae, 47 



b. Immersed ellipsoidal or roundish free-swimming 



aquatics without true leaves Lemnaceae, 48 



c. Marsh or aquatic plants with ribbon-like leaves ; 



stamens and pistils in separate rounded clus- 

 ters Sparganiaceae, 47 



d. Marsh plants with grass-like leaves and perfect 



flowers in racemes Juncaginaceae, 47 



Flowers in the axils of dry chaffy bracts. 



Stems mostly cylindric and hollow; leaf-sheaths 

 split opposite the blade; anthers attached at 



the middle Gramineae, 48 



Stems mostly 3-sided, solid; sheaths entire; an- 

 thers attached at the base Cyperaceae, 48 



Ovary compound; flowers with calyx or corolla or both. 

 Calyx and ovary wholly free from each other; sta- 

 mens mostly 6. (Ovary superior.) 

 Plant rush-like; flowers small, greenish or brown. 



Juncaceae, 49 

 Plant not rush-like. 



Pistils numerous, in a circle Alismaceae, 48 



Pistil one, compound Liliaceae, 49 



Calyx adherent to the ovary. (Ovary inferior.) 

 Flowers regular, stamens 3; capsule 3-celled . . Iridaceae, 60 

 Flowers irregular, stamen 1 (rarely 2) ; capsule 



1-celled Orchidaceae, 61 



Class 2. DICOTYLEDONS 

 Leaves net-veined; flower-parts usually in 4's or 

 5's, never in 3's (exceptions occur in some members of 

 Poppy, Buckwheat, and Spurge families) ; embryo with 

 2 cotyledons; stem with annual layers when perennial. 

 I. APETALOUS SECTION. Corolla none; calyx 

 present, herbaceous or sometimes petal-like (some- 

 times none). (II. on p. 20.) 



A. Trees, shrubs, and woody climbers. (B. on p. 19.) 

 Flowers in catkins, i. e., sessile in narrow scaly spikes, 

 at least the staminate ; pistillate flowers on same or 

 different plant. 

 Leaves opposite; flowers in cup-like bracts Garrya, 173 



