24 American Midland Naturalist Monograph No. 2 



8. Branches with a large pith; fruit a drupe; flowers regular, perfect, numerous, 



small, whitish, cymose ; stamens 5; ovary inferior 



Sambiicus in 146. Caprifoliaceae 



8. Branches with a small pith; fruit a samara; flowers small, greenish, dioe- 

 cious, appearing before the leaves. 

 9. Leaflets 3-5 (rarely 7-9), at least some of them usually coarsely toothed; 



samaras in pairs; stamens 4-6 Acer negundo in 100. AcERACEAE 



9. Leaflets 5-11, entire to shallowly serrate; samaras single; stamens 2.... 



Fraxiniis in 125. Oleaceae 



I. Leaves simple. 



10. Margins toothed or lobed. 



11. Margins toothed, not lobed; shrubs. 



12. Young branchlets more or less quadrangular; leaves serrulate; flowers per- 

 fect, axillary, greenish or purplish; petals 4-6; calyx 4-5-cleft; stamens 



4-5, inserted on the disk; fruit deeply 3-5-lobed 



Euon\imus in 96. Celastraceae 



12. Branchlets terete or nearly so. 



13. Leaves evergreen, small, oval, crenate above the middle; stems slender, 

 trailing; flowers in pairs, nodding, pink, fragrant, about 1 cm. long 



Linnaca in 146. Caprifoliaceae 



13. Leaves otherwise. 



14. Margins dentate or sharply serrate; ovary inferior. 



15. Principal lateral veins 1-5 pairs; corolla of 4 separate petals; 



stamens more than 5; capsule many-seeded 



79. Hydrangeaceae 



15. Principal lateral veins 5-10 pairs; corolla sympetalous, 5-lobed 



or 2-lipped, the 5 stamens inserted on the tube; fruit a 1- 



seeded drupe or a many-seeded capsule ... 146. Caprifoliaceae 



14. Margins crenate; ovary superior; stamens 4-5, inserted with the 



petals and opposite them; fruit a drupe 



Rhamnus in 102. Rhamnaceae 



1 1 . Margins lobed and often toothed. 

 16. Lobes acute, toothed. 



17. Trees; styles 2; fruit a pair of samaras 100. AcERACEAE 



17. Shrubs; style 3-lobed; fruit a 1 -seeded drupe 



Vihurnimi in 146. Caprifoliaceae 



16. Lobes obtuse, entire; shrubs; stamens 5, inserted on the pink sympetalous 



corolla; fruit a 2-seeded drupe 



S^mphoricarpos in 146. CAPRIFOLIACEAE 



10. Margins entire, or merely undulate or slightly crenulate or denticulate. 



18. Plants parasitic on the branches of trees; leaves thick, leathery; fruit a berry 



48. LORANTHACEAE 



18. Not parasitic. 



19. Leaves beneath, and branchlets covered with minute silvery scales; flowers 

 small, axillary, dioecious; calyx 4-parted; corolla 0; stamens 8; fruit a 



drupe I 12. Elaeagnaceae 



19. Leaves not silvery. 



20. Leaves with small black dots; low shrubs; flowers yellow, cymose; 

 sepals and petals each 4 or 5 ; stamens numerous; fruit a capsule 



106. Hypericaceae 



20. Leaves not black dotted. 



21. Leaves large (15-50 cm. long), ovate or cordate. 



22. Leaves visually in whorls of 3 ; flowers whitish, marked with 

 yellow and purple; anther-bearing stamens 2; capsules cylin- 

 drical Caialpa in 140. BiGNONIACEAE 



22. Leaves opposite; flowers purple; anther-bearing stamens 4; cap- 

 sules ovoid Pauloxvnia in 140. BiGNONIACEAE 



21. Leaves usually smaller. 



