18 American Midland Naturalist Monograph No. 7 



30. Flowers in umbels; corolla with 5 reflexed lobes; fruit a 

 many-seeded follicle; seeds with a tuft of silky hairs; 



plants with milky juice 100. Asclepiadaceae 



30. Flowers not in umbels. 



31. Flowers yellow (or white) ; fruit a capsule 



97. Primulageae 



31. Flowers white or greenish, axillary or cymose; fruit 



of 2 united indehiscent 1-seeded nutlets 



1 19. Rubiaceae 



27. Leaves not whorled. 



32. Leaves evergreen, opposite; stems trailing; flowers axillary; 

 plants glabrous. 

 33. Leaf-base narrowed; corolla blue, 5-lobed, 1.5-3 cm long; 

 calyx 5-parted ; stamens 5 ; stigma annular, its apex 

 penicillate Vinca in 99. Apocynaceae 



33. Leaf-base rounded or cordate; corolla white or pink, usual- 



ly 4-lobed, 1-1.5 cm long; calyx 4-toothed; stamens 4, 



stigmas 4; fruit a red double drupe 



Mitchella in 119. Rubiaceae 



32. Leaves rarely evergreen; plants not as above in all respects. 



34. Ovary inferior. 



35. Leaves with stipules, or the petioles connected by a 

 (sometimes bristle-bearing) stipular membrane or 

 line 1 19. Rubiaceae 



35. Leaves without stipules 120. Caprifoliaceae 



34. Ovary or ovaries superior. 



36. Ovaries 2, or if 1, deeply lobed; fruit usually of 2 fol- 



licles; seeds with a tuft of silky hairs; plants usually 

 with milky juice. 

 37. Flowers in cymes, or solitary 99. Apocynaceae 



37. Flowers in umbels 100. Asclepiadaceae 



36. Ovary 1; fruit a capsule or drupe; plants with watery 



juice. 



38. Stamens opposite the corolla-lobes; corolla tube 



short or none; flowers bright yellow, or solitary 



in the axils 97. Primulageae 



38. Stamens alternate with the lobes of the corolla; 

 flowers not yellow (rarely yellowish white). 

 39. Corolla-tube long and slender. 

 40. Stamens 5. 



41. Stigmas 3; pistils 3-carpellate; capsules 



3-loculed, 3-seeded 



Phlox in 104. Polemoniaceae 



41. Stigmas 3; pistils 3-carpellate; capsules 



2-loculed; flowers red 



101. Loganiageae 



40. Stamens 4; stigma simple or two-lobed, the 

 apex of the style recurved ; pistils 2- 



carpellate; capsule 6-20-seeded 



Ruellia in 110. Acanthaceae 



39. Corolla tube short or none, (or more than 3 

 mm thick). 



42. Stamens 5 or 4; capsule 1-loculed 



102. Gentian ageae 



