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.