462 



ILLUSTRATIONS OP TIIK NATURAL ORDERS. 



Stipules sheathing. Nutlets club-shaped, in globular heads. Platanace.*;. 

 Stipules not sheathing or none. 

 Sterile flowers only amentaceous. 



Fruit a kind of drupaceous nut. Leaves pinnate. Jcglandace^. 



Fruit a dry nut, involucrate. Leaves simple. CupulifeRjE. 

 Both kinds of flowers amentaceous. 

 Fruit a samara or a small dry drupe. 



Ovary one-celled ; ovule solitary, erect. Myricaceje. 



Ovary two-celled, two-ovulcd : ovule pendulous. BetulacEjE. 



Fruit a many-seeded follicle : seeds with a coma. S ah cage.*. 



890. Ord. Aristolochiacese {Birthwort Family). Herbaceous or 



climbing shrubby plants, with alternate leaves. Flowers brown 



or greenish, usually solitary. Calyx-tube more or less united with 

 the ovary ; the limb valvate. Stamens six to twelve, epigynous, or 



adherent to the base of the short and thick style : anthers adnate, 



extrorse. Ovary 3-6-celled. Capsule or berry three- to six-celled, 

 many-seeded. Embryo minute, in fleshy albumen. — Ex. Asarum 

 (Wild Ginger, Canada Snakeroot), Aristolochia (Virginia Snake- 

 root)^ Pungent, aromatic, or stimulant tonics ; generally termed 

 Snakeroots, being reputed antidotes for the bites of venomous snakes. 



FIG. -1081. Asarum Canadense. 1082. Calyx displayed, and a vertical sectioa through the 

 rest of the flower. 1083. Cross-section of the ovary ; the upper portion (from which the Hmb 

 of the caJyx is cut away) showing the stamens, the united styles, &c. 1084. A separate sta- 

 men, enlarged. 1085. Vertical section of a seed. 



