9 
A. — Corolla and stamens inserted on the calyx. I, c. p. 12. 
Corolla inserted on the receptacle. 
Stamens inserted on the receptacle and distinct from the co- 
rolla. I, d. p. 14. 
Stamens adherent to the corolla. I, e. p. 14. 
B. — Stigma none. Seeds not enclosed in a pericarp. Embryo 
with more than two cotyledons, — rarely two. 
Gymnosperms. II, b. p. 20. 
Stigma present. Ovules in a pericarp. 
Embryo with two cotyledons. Angiosper ms. II, a. p. 17. 
Embryo acotyledonous. Sporogens. II, C. p. 21. 
C. — Leaves net veined. Ill, a. p. 21. 
Leaves parallel veined. 
Perianth glumaceous, or consisting of imbricated bracts, mostly 
in pairs. Ill, e. p. 25. 
Perianth not glumaceous. 
Perianth adherent to the ovary, flowers complete. 
Ill, b. p. 22. 
Perianth free from the ovary, flowers complete. 
Ill, c. p. 23. 
Perianth none, flowers incomplete. Ill, d. p. 24. 
D. — W i th a distinct stem bearing leaves or branches, and having 
woody tissue and vessels. Acrogens. IV, a. p. 25. 
With no distinction of stem and leaves, but consisting of va- 
riously formed expansions of cellular tissue. 
Tiiaeeogens. IV, b. p. 26. 
In the following pages p. refers to the page of Gray’s “ Field, For- 
est and Garden Botany” on which the order is described. 
The mark f indicates that Gray refers the plants to a different nat- 
ural order. 
When a natural order is given without reference to Gray, the 
plants included in the order are not found in the United States. 
