, p. 11.

16a. Flowers solitary --17.

16b. Flowers 2 or more, in some kind of a cluster --18.

17a. Leaves 2, broadly heart-shape, basal, on long stalks
1b, in =ARISTOLOCHIACEAE=, p. 25.

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. Leav