Jones: Flora of Illinois 35 



4. Shrubs. 



8. Stamens 5; ovary inferior; fruit a berry; branches sometimes spiny 



or prickly 57. Grossulariaceae 



8. Stamens numerous; ovaries superior, separate, or united at the 



base, becoming follicles or drupelets; branches never spiny 



53. ROSACEAE 



1. Leaves pinnately veined. 



9. Lobes of the leaves serrate or crenate. 



10. Fruit of 2-5 follicles; bark shreddy; flowers in corymbs; branches 



never spiny Physocarpus in 53. Rosaceae 



10. Fruit a pome; branches often spiny. 



11. Flowers in cymes; styles united below the middle; pome large, the 

 carpels papery or leathery; branches (but not the twigs) some- 

 times with rather blunt spines Malus in 53. Rosaceae 



11. Flowers in corymbs; pomes small, the carpels bony; branches (and 



twigs) often with sharp spines Crataegus in 53. Rosaceae 



9. Lobes of the lea\es not serrate. 



12. Leaves with a truncate apex and two broad lateral lobes; buds cov- 

 ered by the membranous stipules; flowers large 



Liriodendron in 1 . Magnoliaceae 



12. Leaves not truncate at apex; flowers small. 



13. Leaves pinnatifid with many rounded lobes on each side of the 

 midvein; monoecious shrub with fragrant foliage; flowers in 

 erect catkins; fruit an ovoid nutlet surrounded by subulate 



bracts 68. Myricaceae 



13. Leaves with few lobes. 



14. Leaves with three principal \'eins from the base, aromatic; 



flowers yellow, 6-8 mm broad, in racemes 3-5 cm long 



Sassafras in 74. L.\uraceae 



14. Leaves with one vein from the base, not aromatic; flowers 



greenish, the staminate in catkins; fruit an acorn 



Quercus in 65. Fagaceae 



Section 16. Trees and Shrubs With Alternate, Simple Leaves, the 

 Blades Toothed but Not Lobed 



1. Base of blade symmetrical or nearly so. 



2. Flowers, at least the staminate (except Fagus) in catkins. 



3. Fruit a small several-seeded capsule, the seeds with a tuft of silky 

 hairs; both staminate and pistillate flowers in catkins; stigmas 2, 



often 2-lobed (sometimes 3) ; dioecious shrubs or trees 



69. Salicaceae 



3. Fruit not a capsule; seeds without a tuft of silky hairs; styles 2 or 3. 

 4. Fruit a 1-loculed, 1-seeded nut; plants monoecious. 



5. Styles 3 65. Fagaceae 



5. Styles 2-cleft, or stigmas 2 66. Betulaceae 



4. Fruit a juicy multiple fruit; plants often with milky juice; styles 2 



71. Moraceae 



2. Flowers never in catkins. 



6. Leaves with 1 principal vein from the base. 



7. Leaves with 15-25 pairs of nearly straight, conspicuous lateral veins; 



margins sharply double-serrate; fruit a samara 70. Ui.maceae 



7. Leaves with fewer, less conspicuous veins; fruit not a samara. 

 8. Stamens fewer than 15. 



