40a. Flower-stalk leafless below the spike =PLANTAGINACEAE=, p. 107.
40b. Flower-stalk with several bracts --41.
41a. Leaves entire 9c, in =ORCHIDACEAE=, p. 16.
41b. Leaves toothed 6a, in =SCROPHULARIACEAE=, p. 102.
42a. Flowers in umbels --43.
42b. Flowers in racemes, panicles, flat-topped cl.u.s.ters, or merely 1 or 2 --45.
43a. Leaves almost round, peltate, palmately veined 3a, in =UMBELLIFERAE=, p. 80.
43b. Leaves at least twice as long as broad, with a single mid-vein --44.
44a. Stamens 5 =PRIMULACEAE=, p. 87.
44b. Stamens 10 15, in =ERICACEAE=, p. 85.
45a. Leaves cylindrical, hollow, obtuse. 1a, in =LOBELIACEAE=, p. 113.
45b. Leaves beset on the upper side with long glandular hairs; bog plant with flowers in racemes =DROSERACEAE=, p. 48.
45c. Leaves flat, p.u.b.escent or smooth, but not with long glandular hairs --46.
46a. Sepals and petals each 4 53, in =CRUCIFERAE=, p. 46.
46b. Sepals and petals each 5 --47.
46c. Sepals 6; petals none; flowers minute, green; leaves frequently lobed at the base 4, in =POLYGONACEAE=, p. 25.
47a. Petals united with each other in an irregular corolla =LENTIBULARIACEAE=, p. 105.
47b. Petals separate from each other --48.
48a. Stamens 10; style 1 =ERICACEAE=, p. 84.
48b. Stamens 5 or 10; styles 2 =SAXIFRAGACEAE=, p. 49.
48c. Stamens and pistils each very numerous --49.
49a. Flowers white 64a, in =ROSACEAE=, p. 56.
49b. Flowers yellow 13a, in =RANUNCULACEAE=, p. 36.
--50--
50a. Leaves compound or deeply lobed --51.
50b. Leaves entire or toothed --54.
51a. Flowers in axillary racemes, spikes, or panicles =URTICACEAE=, p. 23.
51b. Flowers terminal, or in terminal cl.u.s.ters --52.
52a. Flowers in umbels; leaves palmately compound =ARALIACEAE=, p. 80.
52b. Flowers in racemes or spikes, or solitary --53.
53a. Leaves deeply pinnatifid; swamp plants with flowers in spikes or solitary =HALORAGIDACEAE=, p. 79.
53b. Leaves lobed, or irregularly pinnately cut or dissected; weedy plants with flowers in racemes 2, in =COMPOSITAE=, p. 114.
54a. Juice milky 3, in =EUPHORBIACEAE=, p. 67.
54b. Juice not milky or colored --55.
55a. Leaves whorled --56.
55b. Leaves all opposite --58.
56a. Aquatic or mud plants with erect stems 2a, in =HALORAGIDACEAE=, p. 79.
56b. Prostrate weedy terrestrial plants =AIZOACEAE=, p. 31.
56c. Erect or ascending terrestrial plants --57.
57a. Leaves more than 2.5 cm. long 4a, in =CORNACEAE=, p. 83.
57b. Leaves 2 cm. long or less 3a, in =PRIMULACEAE=, p. 87.
58a. Flowers in terminal or axillary spikes, racemes, or other cl.u.s.ters --59.
58b. Flowers solitary or few in the axils of the leaves --61.
59a. Leaves less than 5 mm. long 1a, in =GENTIANACEAE=, p. 88.
59b. Leaves more than 2 cm. long --60.
60a. Inflorescence chiefly terminal, panicled 2, in =COMPOSITAE=, p. 114.
60b. Inflorescence chiefly axillary =URTICACEAE=, p. 23.
61a. Flowers on long pedicels 2, in =CARYOPHYLLACEAE=, p. 31.
61b. Flowers on short pedicels or sessile --62.
62a. Stem erect, repeatedly branched; leaves linear to oblong =ILLECEBRACEAE=, p. 31.