20 American Midland Naturalist Monograph No. 7 



14. Ovary deeply 4-iobed, the style arising between the lobes; 



plants usually with a mint odor; corolla usually bilabiate, 



rarely nearly regular 118. Labiatae 



13. Fruit of only 1 nutlet, or else a capsule with many seeds. 



15. Flowers reflexed and becoming appressed to the stem in fruit; 



fruit a single nutlet in the bottom of the calyx; calyx-teeth 

 hooked at the tip; corolla purplish; median and lower 



leaves slender-petioled 117. Phrymaceae 



15. Flowers not reflexed and appressed to the stem; calyx-teeth 

 not hooked. 



16. Ovary inferior; stamens 3 123. Valerianaceae 



16. Ovary superior; stamens usually 2, or 4, rarely 5 



108. Scrophulariaceae 



Section 7. Dicotyledonous Herbs (Except Smilax) With Alternate Leaves 



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



involucre of bracts 125. Compositae 



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

 subtended by an involucre of bracts. 

 2. Stem-leaves reduced to minute scales; corolla irregular, spurred; plants 



small, growing in wet soil 112. Lextibulariaceae 



2. Stem-leaves not all reduced to scales. 



3. Leaves with stipules, these sometimes united to form a sheath (some- 

 times fugacious). 

 4. Stipules united and forming a membranous sheath at the nodes; 



fruit an achene 32. Polygonaceae 



4. Stipules not sheathing; fruit a several-seeded capsule or pod. 



5. Petals none; fruit a small 3-loculed capsule 43. Euphorbiaceae 



5. Petals present; plants pubescent; fruit a 1-loculed pod. 



6. Leaves sessile or nearly so; flowers yellow, papilionaceous 



Crotalaria in 54. Leguminosae 



6. Leaves petioled; flowers greenish white 



Hybanthus in 11. Violaceae 



3. Leaves without stipules, or stipules minute. 



7. Petals separate, or none; calyx sometimes petal-like. 



8. Plants with milky juice; stem umbellately branched above; upper- 

 most leaves whorled; involucres with white petal-like append- 

 ages 43. Euphorbiaceae 



8. Plants without milky juice; stems and leaves not as above. 



9. Calyx and corolla absent; flowers in spikes; leaves cordate, 



petioled 33. Saururaceae 



9. Calyx present; corolla present or absent. 

 10. Flowers small, green. 



11. Flowers in umbels; perianth 6-parted; fruit a berry 



Smilax in 130. Liliaceae 



11. Flowers not in umbels; perianth not 6-parted; fruit not 

 a berry. 

 12. Plants perennial, pubescent; fruit a capsule, with 



more than 1 seed; leaves small and narrow 



12. Cistaceae 



12. Plants annual, glabrous or pubescent; fruit an 

 achene, or a 1 -seeded capsule. 

 13. Flowers all in loose cymose axillary clusters; style 



