Jones: Flora of Illinois 9 



4. Stems either twining or climbing (tendrils sometimes present); or 

 else cactus plants with conspicuously jointed, succulent, spiny 



stems Section 10, p. 26 



2. Aquatic plants, floating on or submerged in water (sometimes growing on 

 muddy or sandy shores) Section 11, p. 27 



B. Trees and Shrubs (Including Woody Climbers and Trailers) 



11. Gymnosperms. Lea\-es needle-like (acicular), linear, scale-like, or subulate, 



evergreen (deciduous in Larix and Taxodium) Section 19, p. 39 



1 1. Angiosperms. Lea\es not as above: "broadleaf" trees and shrubs (except 

 Hudsonia) . 

 12. Flowers appearing with or after the leaves. 



13. Leaves opposite or whorled Section 12, p. 28 



13. Leaves alternate. 



14. Leaves compound Section 13, p. 31 



14. Leaves simple. 



15. Leaves entire Section 14, p. 32 



15. Leaves toothed or lobed, not entire. 



16. Leaves lobed Section 15, p. 34 



16. Leaves toothed, but not lobed Section 16, p. 35 



12. Flowers on leafless or almost leafless twigs, appearing before the leaves 



(or in autumn when they are falling, in Hamamelis) 



Section 1 7, p. 37 



Group IL Fern and Fern-allies. Plants without flowers or seeds, reproduc- 

 ing by spores borne in sporangia Section 18, p. 38 



Key to the Families 



Section 1. Grasses, Sedges, and Rushes 



1. Flowers enclosed by chaffy scales; perianth none, or of bristles; fruit a grain 

 or an achene. 

 2. Stem cylindrical and usually hollow except at the nodes; leaves in 2 rows 



on the stem, the sheaths usually split; fruit a grain 146. Gramineae 



2. Stem cylindrical or triangular, solid, the nodes usually not conspicuous; 



sheaths not split; fruit an arhene 145. Cvperaceae 



1. Flowers not enclosed by chaffy scales; perianth 6-parted; stems terete; fruit 

 a capsule 131. Jttncaceae 



Section 2. Herbs With Compound (or Deeply Divided) Leaves 



1. Plants without leafy stems, the leaves all basal. 



2. Leaves 2-cleft; flowers white; fruit a capsule opening by a lid 



9. Podophvllaceae 



2. Leaflets 3 or more; fruit not opening by a lid. 



3. Flowers on a spadix surrounded by a spathe; fruit a berry 



Arisaema in 141. Araceae 



3. Flowers in racemes or umbels. 

 4. Leaflets 3. 



5. Leaflets entire; flowers regular; stamens 10 38. Oxalidaceae 



5. Leaflets not entire. 



6. Flowers papilionaceous; stamens 10 54. Leguminosae 



6. Flowers regular; stamens numerous 53. Rosaceae 



4. Leaflets numerous; flowers irregular 14. Fumariaceae 



