Jones: Flora of Illinois 37 



Section 17. Flowers on Leafless (or Almost Leafless) Twigs 



1. Leaf-buds and leaf-scars opposite. 



2. Flowers perfect, large, violet, in terminal panicles; leaves large, cordate, 

 petioled, pubescent; fruit a capsule with numerous small winged seeds 



Paulownia in 1 09. Bignoniaceae 



2. Flowers unisexual (rarely perfect), the plants dioecious, polygamous, or 

 monoecious; styles or stigmas 2; fruit of samaras. 

 .3. Bud-scales scurfy brown or black; bundle-scars forming a crescent- 

 shaped line; calyx small, 4-cleft or obsolete; stamens usually 2; fruit 



a single samara Fraxinus in 98. Oleaceae 



3. Bud-scales not scurfy, paler; bundle-scars not forming a curved line; 

 calyx usually 5-lobed; stamens 4-10, usually 8; fruit a pair of 



samaras 50. Aceraceae 



1. Leaf -buds and leaf-scars alternate. 



4. Flowers (at least the staminate) in catkins, apetalous. 

 5. Style 2-cleft, or stigmas 2 (or 3 or 4). 

 6. Perianth none. 



7. Fruit a many-seeded capsule; plants dioecious 69. Salicaceae 



7. Fruit a I-seeded nut; plants monoecious 66. Betulaceae 



6. Perianth of 4 sepals; fruit a syncarp 71. Moraceae 



5. Style or stigmas 3 (or 4) ; fruit a 1-seeded nut 65. Fagaceae 



4. Flowers not in catkins. 



8. Branches with sharp stipular prickles; plants dioecious; sepals 0; petals 

 4-5, greenish yellow; stamens 4 or 5 ; pistils 2-5; leaves pinnate 



Zanthoxylum in 34. Rutaceae 



8. Branches not prickly; leaves simple. 



9. Flowers white (or pink), perfect; petals 5; sepals 5. 



10. Style 1 Prunus in 53. Rosaceae 



10. Styles 5 Amelanchier in 53. Rosaceae 



9. Flowers not white. 



11. Corolla papilionaceous, red-purple; flowers perfect, in umbel-like 



clusters; stamens 10; fruit a legume 



Cercis in 54. Leguminosae 



11. Corolla not papilionaceous; fruit not a legume. 



12. Flowers with 4 linear yellow petals; calyx 4-parted; stamens 

 8, short; styles 2; fruit a capsule; flowers appearing in 



autumn when the leaves are falling 



Hamamelis in 58. Hamamelidaceae 



12. Flowers greenish, purplish, or yellowish, appearing in spring. 



13. Flowers greenish or purple. 



14. Stamens numerous; petals 6; sepals 3; leaves entire, 



alternate 2. Annonaceae 



14. Stamens 2-9; petals 0. 



15. Stamens 2-4; calyx 0; leaves opposite 



Forestiera in 98. Oleaceae 



15. Stamens 4-9, inserted on the calyx; calyx 4-9 cleft; 



trees with serrate alternate leaves 



70. Ulmaceae 



13. Flowers yellowish or yellow; leaves entire or lobed. 



16. Sepals 5; petals 5; stamens 5 49. Anacardiaceae 



16 Sepals 6 or 4. 



