16 American Midland Naturalist Monograph No. 2 



36. Corolla about as long as the calyx; fruit a 3-seeded drupe 



Triosteum in 146. Caprifoliaceae 



36. Corolla much longer than the calyx; fruit dehiscent, usually 

 more than 3-seeded. 

 37. Stamens opposite the corolla-lobes; corolla-tube short or 

 none; flowers bright yellow, or solitary in the axils.... 



121. Primulaceae 



37. Stamens alternate with the lobes of the corolla; flowers not 

 yellow. 

 38. Corolla-tube long and slender. 



39. Stamens 5; stigmas 3; pistil 3-carpellate; capsule 



3-loculed, 3-seeded 



Phlox in 131. POLEMONIACEAE 



39. Stamens 4; stigma simple or 2-lobed, the apex of 

 the style recurved; pistil 2-carpellate ; capsule 



6-20-seeded Ruellia in 142. Acanthaceae 



38. Corolla-tube short or none; capsule 1-loculed, many- 

 seeded; plants glabrous or nearly so 



126. Gentianaceae 



Section 6. Dicotyledonous Herbs With Toothed 

 or Lobed Opposite or Whorled Leaves 



1 . Flowers sessile in dense heads on a common receptacle surrounded by an involucre of 

 bracts. 

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

 rigid spine-like tips; stamens 4, distinct 148. DiPSACACEAE 



2. Stem not prickly; chaff of the receptacle not as above, sometimes absent; stamens 5, 



united by their anthers (syngenesious) 152. 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 sometimes absent. 

 4. Leaves deeply lobed. 



5. Plants glabrous; leaves 2, peltate; flower solitary; petals 6-9, white 



Podophyllum in 66. Berberidaceae 



5. Plants (at least the stem) pubescent; leaves 2 or more, not peltate; flowers 

 usually more than 1 . 



6. Petals present; stamens 10; styles 5; fruit of 5 carpels 85. Geraniaceae 



6. Petals none, but the sepals colored and petal-like; stamens more than 10; 



fruit of numerous achenes 62. RanunculacEAE 



4. Leaves merely toothed. 



7. Plants with milky juice (or if with watery juice, the pubescence stellate) ; the 

 fruit deeply 3-lobed; corolla none, but the flowers surrounded by an often 



corolla-like involucre 94. EuPHORBlACEAE 



7. Plants with watery juice; fruit not 3-lobed. 

 8. Mowers green, without petals; fruit 1 -seeded. 



9. Plants scurfy with minute whitish scales; stipules none 



A triplex in 51. Ciienopodiaceae 



9. Plants glabrous, or pubescent with slender, sometimes stinging hairs, never 



scurfy or scaly; leaves stipulate 46. Urticaceae 



8. Flowers with white or colored [)etals; fruit usually with more than 1 seed. 



10. Petals large (1 cm. or more in length), pink or [nirphsh; leaves 3-4- 



ribbed; plants bristly-hairy 114. Melastomaceae 



10. Petals small (less than 1 cm. in length); leaves not ribbed; plants not 

 bristly-hniry. 

 II. Ovary inferior; seeds with a tuft of soft hairs, or else the fruit with 



short, hooked hairs 115. Onagraceae 



II. Ovary superior; seeds without hairs; fruit never bristly 



77. Saxifragaceae 



