17b. Leaves not heart-shape 20, 20, in =LILIACEAE=, p. 12. 18a. Divisions of the perianth (4 to 6) all essentially alike --19. 18b. Perianth differentiated into sepals and 2 or 3 colored petals --21. 19a. Flowers in umbels --20. 19b. Flowers in dense round heads; petals 5 2a, in =UMBELLIFERAE=, p. 80. 19c. Flowers in spikes, racemes, or panicles 38, in =LILIACEAE=, p. 13. 20a. Ovary inferior, appearing below the perianth as a swelling at the apex of the stalk; flowers bright yellow; leaves linear =AMARYLLIDACEAE=, p. 14. 20b. Ovary inferior; flowers blue or white, terminating a flattened winged leafless flower-stalk 3a, in =IRIDACEAE=, p. 15. 20c. Ovary superior, i. e., in the center of the flower and separate from the perianth 31, in =LILIACEAE=, p. 13. 21a. Flowers in dense heads, yellow, 1 cm. wide or smaller =XYRIDACEAE=, p. 9. 21b. Flowers in umbels, blue or white, 2 cm. wide or larger =COMMELINACEAE=, p. 9. 22a. Flowers blue; ovary superior (defined under _20c_); stamens distinct from the other parts of the flower --23. 22b. Ovary inferior (defined under _20a_); floral structure complex; stamens attached to other parts of the flower and not resembling ordinary stamens in form or structure =ORCHIDACEAE=, p. 15. 23a. Leaves triangular-heart-shape at base; marsh plants 1a, in =PONTEDERIACEAE=, p. 10. 23b. Leaves not heart-shape at base =COMMELINACEAE=, p. 9. GROUP 4, DICOTYLEDONES 1a. Foliage leaves all or principally basal; flower-stalk either completely leafless, or bearing a single pair of opposite leaves only. Bracts and scale-leaves are not considered foliage leaves --2. 1b. Stem-leaves present on the stem, either one or more in number, and not limited to a single opposite pair --3. 2a. Leaves compound --7. 2b. Leaves simple --18. 3a. Stem-leaves all or chiefly opposite or whorled (the bracts of the flower clusters may be alternate) --4. 3b. Stem-leaves all or chiefly alternate --5. 4a. Flowers small and inconspicuous, the perianth none or greenish or chaffy, and never petal-like in appearance --50. 4b. Flowers with a white or colored petal-like perianth --66. 5a. Flowers small and inconspicuous, without any white or colored petal-like perianth --118. 5b. Flowers large or small, but with a white or colored petal-like perianth --6. 6a. Flowers small, not exceeding 3 mm. in length or breadth --144. 6b. Flowers larger, more than 3 mm. in length or breadth --166. --7--