Jones : Flora of Illinois 15 



35. Leaves equitant; flowers blue or white; 



ovary inferior; stamens 3 136. Iridaceae 



35. Leaves not equitant; ovary superior: sta- 

 mens 6 130. LiLIACEAE 



Section 4. Mostly Monocotyledonous Herbs (Except Grasses, 

 Sedges, and Rushes) With Leafy Stems 



1. Flowers in dense heads or spikes. 



2. Leaves cordate; flowers blue, 2-lipped ; stamens 6 



Pontederia in 134. Pontederiaceae 



2. Leaves not cordate. 



3. Plants growing in wet places: flowers greenish. 



4. Spikes cylindrical, the upper part staminate, the lower pistillate; 

 plants 2-3 m tall 143. Typhaceae 



4. Heads spherical; plants not so tall 144. Sparganiaceae 



3. Plants of dry ground: flowers not green. 



5. Leaves spiny- or bristly-margined: plants with watery juice 



Eryngium in 92. Umbelliferae 



5. Lea\'es smooth-margined; plants with milky juice 



Tragopogon in 125. Compositae 



1. Flowers not in dense heads. 

 6. Ovary or ovaries superior. 



7. Ovaries 3 or 6, nearly separate; stamens 3 127. Juncaginaceae 



7. Ovary 1, compound. 



8. Flowers irregular, blue, enclosed or subtended by a small spathe; 



petals 3, unequal Commelina in 133. Commelin.aceae 



8. Flowers regular. 



9. Flowers blue or purple; filaments pubescent; juice mucilaginous 



Tradescantia in 133. Commelinaceae 



9. Flowers not blue (sometimes lavender) ; filaments glabrous or 

 nearly so. 



10. Stamens 3 134. Pontederiaceae 



10. Stamens 6 130. Liliaceae 



6. Ovary inferior, compound. 



11. Stamens 3; flowers regular; leaves equitant 136. Iridaceae 



11. Stamens 1 or 2 ; flowers irregular; leaves not equitant 



140. Orchidaceae 



Section 5. Dicotyledonous Herbs (Except Trillium) With Opposite 



or Whorled Entire Leaves 



1. Flowers sessile in dense heads on a common receptacle surrounded or sub- 

 tended by an involucre of bracts; fruit an achenc. [Pycnanthemum 

 (Labiatae), with flowers in dense head-like clusters, might also be sought 

 here.] 

 2. Stem with small prickles; chaflP of the receptacle (among the flowers) 

 with long rigid spine-like tips; stamens 4, distinct 124. Dip.sacaceae 



2. Stem not prickly; chaflf of the receptacle not as above, sometimes absent; 



stamens 5, united by their anthers (syngenesious) 125. Compositae 



1. Flowers not sessile in dense heads on a common receptacle surrounded or 

 subtended by an involucre of bracts. 



3. Corolla of separate petals (or apparently so), or corolla absent (the calyx 



sometimes petal-like). 



