Jones: Flora of Illinois 17 



19. Petals white (sometimes absent) ; 

 leaves with ordinary flat blades; 



stems usually soft 



24. Caryophyllaceae 



19. Petals yellow; leaves small, scale- 

 like or subulate, appressed or 

 nearly erect ....19. Hypericaceae 

 18. Sepals unequal, the 2 outer much nar- 

 rower than the 3 inner ones; petals 

 yellow, greenish, or purplish; stems 



rigid and almost woody 



12. Clstaceae 



15. Sepals united at least below. 



20. Flowers surrounded by a calyx-like involucre, 

 the calyx blue or pink, corolla-like; sta- 

 mens 3-5, e.xserted 31. Nyctaginaceae 



20. Flowers not surrounded by an involucre; 

 calyx green. 

 21. Petals and stamens hypogynous, or the 



flowers without a pistil 



24. Caryophyllaceae 



21. Stamens inserted on the calyx. 



22. Stigma capitate; style 1; petals pres- 

 ent (absent in Peplis) ; fruit a 



capsule 75. Lythraceae 



22. Stigmas 2, sessile or nearly so; petals 



none; fruit a utricle 



Scleranthus in 29. Illecebraceae 



3. Corolla sympetalous (petals united, at least below). 

 23. Corolla irregular (flowers zygomorphic) . 



24. Fruit of 4 small nutlets; ovary 4-lobed; stem 4-angled; leaves 



usually glandular-punctate; plant usually with mint odor 



1 18. Labiatae 



24. Fruit a capsule ; ovary not 4-lobed ; plants without mint odor. 



25. Seeds few, borne on hooks in the elastically dehiscent capsule 



1 10. Acanthaceae 



25. Seeds numerous, not borne on hooks; capsule not elastically 



dehiscent. 



26. Ovary 1-loculed with 2 parietal placentae; corolla 3-5 cm 



long, gibbous, campanulate, 5-lobed and somewhat 2- 



lipped ; capsule 10-15 cm long, the beak longer than the 



body; odoriferous glandular annuals 



114. Martyniaceae 



26. Ovary 2-Ioculed; placentae axial ....108. Scrophularlaceae 

 23. Corolla regular or nearly so (flowers actinomorphic) . 

 27. Leaves whorled. 



28. Flowers in a head surrounded by 4 white bracts; petals 4; 



stamens 4; drupe red 90. Cornaceae 



28. Flowers not as above. 



29. Flowers in a pyramidal panicle 30-60 cm long; fruit a 

 compressed, 2-valved capsule; corolla greenish yellow 



with brownish purple dots 



Frasera in 102. Gentianaceae 



29. Inflorescence otherwise. 



