KEY TO THE ORDERS AND FAMILIES xi 



Flowers irregular; tndosperm none; seeds very minute and numerous. 



Order 10. Okchidales. 

 Represented hy one family. Fam. 23. Orchidaccac. 469 



Subclass 2. DICOTYLEDONES 485 



Petals distinct or wanting, exceptions noted on page 485. Series 1. Choripctal'ac. 



Petals united at least at base. Series 2. Sympctalac. 



Series 1. Choripetalae 485 



Calyx and corolla none. 



Herbaceous plants ; ours with flowers in a spike subtended by petaloid bracts. 



Order 11. Piperales. 

 Represented by one family. Fam. 24. Sauniraceae. 485 



Trees or shrubs ; staminate and pistillate flowers in aments. 



Fruit a many-seeded capsule ; seeds with coma. Order 12. Salicales. 



Represented by one family. Fam. 25. Salicacea-e. 486 



Fruit 1-seeded, forming a waxy drupe. " Order 13. Myricales. 



Represented by one family. Fam. 26. Myricaccac. 508 



Calyx present; corolla none, except in the pistillate flowers of Jiujlaiis. 

 Flowers, at least the staminate, in aments ; trees and shrubs. 



Leaves odd-pinnate; fruit a nut. Order 14. Jlrlandale.s. 



Only one family. Fam. 27. Juglandaceae. 509 



Leaves simple. Ordtr 15. Fagale.s. 



Staminate and pistillate flowers in aments, the latter only 2-3-flowered, the nut 



enclosed by a husk-like involucre in Corylus. Fam. 28. Bctulaceae. 510 



Staminate flow-ers in aments, the pistillate subtended by an involucre, becoming a cup 



or bur in fruit. Fam. 29. Fagaccac. 514 



Flowers not in aments. 



Ovary superior. Order 16. Urticales. 



. Trees; fruit (in ours) a drupe. Fam. 30. Ulniaceac. 523 



Herbs; fruit an achene. Fam. 31. Urticaccac. 523 



Ovary wholly or partly inferior. 



Ovary 1-celled ; parasitic plants. Order 17. Santalales. 



Flowers perfect ; plants parasitic on roots of other plants. 



Fam. 32. Santalacrae. S27 

 Flowers dioecious ; plants parasitic on stems of trees and shrubs. 



Fam. 33. LorantJiaccac. 528 

 Ovary several-celled; flowers perfect. Order 18. Aristolochiales. 



Only one family. Fam. 34. Aristolochiaccac. 534 



