140 LESSONS IN BOTANY 



17. Leaves opposite IS. 



17. Leaves alternate 19. 



18. Fruit a pyxis, opening by a lid. 

 18. Fruit a capsule, opening by 4 or 5 valves. 

 19. Fruit a capsule, 5-celled, 5-horned. 

 19. Fruit a fleshy, 4:-oo-seeded berry. 

 19. Fruit dry, 1-seeded, opening by a lid. 

 20. Flowers on a spadix with a spathe. 

 20. Flowers in a long, naked spike. Stamens 6 or 7. 

 20. Flowers solitary, axillary, minute. Water-plants. .. .21. 

 21. Stamen 1. Leaves opposite. 

 21. Stamens 2. Leaves alternate, dissected. 

 21. Stamens 12-24. Leaves whorled, dissected. 



22. Flowers, none of them in aments 23. 



22. Flowers (imperfect), the sterile only in aments.. . .34:. 



22. Flowers (imperfect), both the sterile and the fertile in aments. ..35. 



23, Leaves opposite 24. 



23. Leaves alternate 27. 



24. Stamens 2. * Order 99 



24. Stamens 3. Parasites. Mistletoe— Lwanths. 108 



24. Stamens 4-9 25. 



25. Fruit a double, 2-winged samara. * Oi'der 40 



25. Fruit not winged 26. 



26. Seeds 6. Low shrubs. Box» Spurgeworts. 112 



26. Seed 1. Shrubs. Oleasters. Ill 



27. Stylo or stigma 1. Seed 1 28. 



27. Styles or stigmas 2 31. 



27. Styles or stigmas 3-9 32. 



28. Calyx free from the ovary. . . .29. 

 28. Calyx adherent to the ovary. . . .30 



29. Anthers opening by valves. * Laurels. 118 



29. Anthers opening by slits. * Daphnads. 107 



30. Seeds 2-4. Shrubs. Sandalworts. 109 



30. Seed 1. Trees. * Order 65 



31. Stamens numerous. * Order 62 



31. Stamens as many as the calyx lobes. Elmworts. 113 



32. Leaves pinnate. Pistils 5. {PrickCy Ash.) Order 37 



82. Leaves simple, linear, evergreen. Crowberries. 116 



32. Leaves simple, not linear 33. 



33. Flowers 3- parted. Fruit dry. {Stillingia.) Spurgeworts. 112 



83. Flowers 4 or 5-parted. Fruit fleshy. * {Buckthorns.) Order 43 

 34. Nut or nuts in a cup or involucre. Leaves simple. * Mastworts. 119 

 84. Nut naked, a tryma (§ 172). Leaves pinnate. ^Walnuts '; Hickorywm'ts. 117 



