Jones: Flora of Illinois 29 



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



sharply double-serrate; fruit a samara 43. UlmaceaE 



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

 8. Stamens fewer than 15. 



9. Anthers opening by apical pores; pith of the branches solid 



120. Ericaceae 



9. Anthers opening lengthwise; flowers white or greenish. 

 10. Pith chambered, or separated by woody plates. 



1 1 . Leaves stellate-pubescent beneath; flowers perfect, white, nodding, 

 on slender pedicels; calyx 4-toothed; petals 4, united below; 



fruit dry, bony within, 1 -seeded, 4-winged 



Halesia in 124. StyracaceAE 



1 1. Leaves not stellate-pubescent. 



12. Flowers greenish, dioecious; fruit a drupe 



Nyssa in 117. CoRNACEAE 



12. Flowers white, perfect; fruit a 2-valved, ellipsoid, 2-loculed, 

 several-seeded capsule tipped with the 2 styles 



78. ESCALLONIACEAE 



10. Pith solid. 



13. Stems climbing, twining, or trailing; leaves elliptical, finely serrate, 

 glabrous; flowers in terminal racemes; capsules subglobose, yel- 

 low, with crimson seeds Celaslrus in 96. Celastraceae 



13. Stems erect. 



14. Flowers solitary or clustered in the axils; fruit a small, berry- 

 like drupe with 4-8 bony nutlets. ...97. Aquifoliaceae 



14. Flowers in small dense panicles or corymbs; fruit a 3-loculed 



capsule 102. Rhamnaceae 



8. Stamens 15 or more; fruit a drupe, pome, or follicle 83. RoSACEAE 



6. Leaves with 3 or more principal veins from the base. 



15. Leaves cordate, slender-petioled, abruptly acuminate, sharply serrate; trees 



104. TiLIACEAE 



15. Leaves not cordate. 



16. Low shrubs; pith continuous; flowers white; fruit a capsule; leaves ovate 



or elliptic-lanceolate, short-petioled, finely toothed 



Ceanoihus in 102. Rhamnaceae 



16. Trees or shrubs; pith of branches chambered; flowers greenish, apetalous; 

 fruit a red drupe ; leaves ovate-lanceolate or lanceolate, acuminate, 



scabrous '. Ce//is in 43. Ulmaceae 



Base of blade noticeably asymmetrical. 



17. Leaves sinuately or obtusely toothed, obovate or oval; flowers appearing in autumn 

 when the leaves are falling; petals 4, yellow, linear; calyx 4-parted; stamens 8, 



short; styles 2; fruit a capsule Hamamelis in 81. Hamamelidaceae 



17. Leaves serrate; flowers appearing in spring; fruit not a capsule. 



18. Leaves cordate, glabrous, or the lower surface pubescent or with tufts of hairs 

 in the axils of the veins; flowers appearing after the leaves, in drooping 

 cymes, small, fragrant, the jjeduncle united with the membranous bract; fruit 



small, globose, indehiscent 104. TiLIACEAE 



18. Leaves scabrous or hispidulous; flowers apetalous, appearing with or before 

 the leaves. 



19. Flowers in catkins: leaf-buds acute Oslr^a in 41. Betulaceae 



19. Flowers not in catkins; leaf-buds obtuse 43. Ulmaceae 



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



, Leaf-buds and leaf-scars opposite; flowers dioecious, polygamous, or monoecious; 

 styles or stigmas 2 ; fruit of samaras. 

 2. Bud-scales scurfy brown or black; bundle-scars forming a crescent-shaped line; 



calvx small, 4-cleft or obsolete; stamens usually 2; fruit a single samara 



Fraxinus in 125. Oleaceae 



