The Plants of Michigan Part 52

38b. Native species, trees or shrubs, growing in woods, fields, or thickets; frequently with thorns (spring) --40.

39a. Leaves finely serrulate or entire =Pear, Pyrus communis.=

39b. Leaves coa.r.s.ely serrate or somewhat lobed =Apple, Pyrus malus.=

40a. Shrubs or small trees, without thorns --42.

40b. Bushy trees or shrubs, with thorns or stiff thorn-like branches, and with flowers generally 1.5-2.5 cm. across --41.

41a. Flowers pink, very fragrant =Wild Crab, Pyrus coronaria.=

41b. Flowers white (Hawthorn, the genus Crataegus). Several species of this genus occur in the state, for the identification of which the Manual must be used.

42a. Mid-vein glandular above (shrubs 1-3 m. tall; flowers white or pink) (Chokeberry) --43.

42b. Mid-vein not glandular (shrubs or trees, 1-10 m. tall; flowers white) (Juneberry) --44.

43a. Leaves glabrous beneath =Chokeberry, Pyrus melanocarpa.=

43b. Leaves tomentose beneath =Chokeberry, Pyrus arbutifolia var. atropurpurea.=

44a. Petals 15-25 mm. long --45.

44b. Petals 5-12 mm. long --46.

45a. Mature leaves glabrous =Juneberry, Amelanchier canadensis.=

45b. Mature leaves p.u.b.escent beneath =Juneberry, Amelanchier canadensis var. botryapium.=

46a. Flowers in racemes --47.

46b. Flowers solitary, or in small cl.u.s.ters of 2-4 =Juneberry, Amelanchier oligocarpa.=

47a. Leaves coa.r.s.ely dentate, with about 1 tooth for each lateral vein =Juneberry, Amelanchier spicata.=

47b. Leaves finely serrate, with about 2-3 teeth for each lateral vein =Juneberry, Amelanchier oblongifolia.=

48a. Flowers yellow --49.

48b. Flowers white, pink, purple, or rose, never yellow --63.

49a. Plant with basal trifoliate leaves, resembling strawberry (1-3 dm.

high; late spring) =Barren Strawberry, Waldsteinia fragarioides.=

49b. Plants with leafy stems --50.

50a. Flowers solitary in the axils of foliage leaves, on long peduncles (trailing or creeping plants; flowers in late spring and summer) --51.

50b. Flowers in narrow terminal spike-like racemes (3-8 dm. high; summer) (Agrimony) --52.

50c. Flowers in irregular or spreading cl.u.s.ters --55.

51a. Leaflets 5 =Five-finger, Potentilla canadensis.=

51b. Leaflets 7-25 =Silver Weed, Potentilla anserina.=

52a. Princ.i.p.al leaflets more than 3 times (about 3-1/2) as long as wide =Agrimony, Agrimonia parviflora.=

52b. Princ.i.p.al leaflets less than 3 times (about 2-1/2) as long as wide --53.

53a. Leaves nearly glabrous beneath, or with scattered spreading hairs =Agrimony, Agrimonia gryposepala.=

53b. Leaves softly p.u.b.escent beneath --54.

54a. Leaves distinctly glandular beneath =Agrimony, Agrimonia striata.=

54b. Leaves not glandular beneath =Agrimony, Agrimonia mollis.=

55a. Princ.i.p.al leaves palmately compound with 5-7 leaflets (Cinquefoil) --56.

55b. Princ.i.p.al stem-leaves with 3 leaflets, or pinnately compound with several leaflets --58.

56a. Leaves silvery-white beneath, laciniately toothed (1-4 dm.

high; late spring and summer) =Silvery Cinquefoil, Potentilla argentea.=

56b. Leaves not silvery-white beneath (3-10 dm. high; summer) --57.

57a. Terminal leaflet more than 3 times as long as wide =Cinquefoil, Potentilla recta.=

57b. Terminal leaflet less than 3 times as long as wide =Cinquefoil, Potentilla intermedia=

58a. Flowers about 4 mm. wide (2-6 dm. high; spring) =Spring Avens, Geum vernum.=

58b. Flowers 6 mm. wide, or wider --59.

59a. Princ.i.p.al leaves with lobed leaflets, of which the terminal is the largest; leaf-axis bearing also some small leaflets between those of usual size (4-12 dm. high; late spring and summer) (Avens) --60.

59b. Princ.i.p.al leaves with toothed or pinnately cleft leaflets, the lateral ones about equaling the terminal one in size, and without any small scattered leaflets (3-8 dm. tall; summer) (Cinquefoil) --61.

60a. Terminal leaflet cordate at base =Avens, Geum macrophyllum.=

60b. Terminal leaflet wedge-shape or acute at base =Avens, Geum strictum.=

61a. Leaflets 3 =Cinquefoil, Potentilla monspeliensis.=

61b. Leaflets 5-15 --62.

62a. Leaflets crenate =Cinquefoil, Potentilla paradoxa.=