The Plants of Michigan Part 64

LYTHRACEAE, the Loosestrife Family

Herbs or shrubs, with opposite or alternate entire leaves; receptacle cup-shape or tubular, bearing the 5-7 petals and sepals at its margin, and the 6-12 stamens on its inner surface; ovary superior.

1a. Stem shrubby (aquatic, stems 1-3 m. long; flowers pink, summer) =Water Loosestrife, Decodon verticillatus.=

1b. Stem herbaceous (4-10 dm. high; flowers purple, summer) --2.

2a. Flowers solitary in the axils; leaves mostly alternate =Loosestrife, Lythrum alatum.=

2b. Flowers in terminal panicles; leaves opposite or whorled =Loosestrife, Lythrum salicaria.=

MELASTOMACEAE, the Melastoma Family

Herbs, with opposite leaves with 3-5 princ.i.p.al veins; receptacle urn-shape, bearing 4 sepals and 4 petals at its edge; stamens 8; ovary 4-celled, superior.

One species in Michigan, 3-4 dm. high, with purple flowers in late summer =Meadow Beauty, Rhexia virginica.=

ONAGRACEAE, the Evening Primrose Family

Herbs with opposite or alternate simple leaves and regular flowers; sepals and petals each 4 (or 2 in one genus), stamens 8 (or 2 in one genus), attached to the summit or inside of a tubular receptacle; ovary 2-4-celled, inferior.

1a. Aquatic plant of shallow water or muddy ground, with prostrate stem (flowers minute, axillary; petals small or none, summer) =Water Purslane, Ludvigia pal.u.s.tris.=

1b. Land plants with erect or ascending stems --2.

2a. Petals minute, greenish (3-8 dm. high; late summer) =False Loosestrife, Ludvigia polycarpa.=

2b. Petals yellow --3.

2c. Petals white, pink, purple, or red --9.

3a. Sepals borne at the summit of the ovary (5-10 dm. high; summer) =False Loosestrife, Ludvigia alternifolia.=

3b. Sepals borne at the summit of the slender tubular receptacle, which is prolonged beyond the ovary --4.

4a. Stamens all equal in length (Evening Primrose) --5.

4b. The alternate stamens longer (3-8 dm. high; summer) (Sundrops) --8.

5a. Leaves deeply dentate or pinnatifid (2-5 dm. high; early summer) =Evening Primrose, Oenothera laciniata.=

5b. Leaves entire or undulate or finely toothed (5-12 dm. high; summer) --6.

6a. Hairs on the stem with broad reddish bases =Evening Primrose, Oenothera muricata.=

6b. Hairs on the stem none, or without swollen bases --7.

7a. Stem and foliage glabrous, or with spa.r.s.e spreading hairs =Evening Primrose, Oenothera biennis.=

7b. Stem and foliage densely but closely appressed-p.u.b.escent =Evening Primrose, Oenothera rhombipetala.=

8a. Petals 5-10 mm. long =Sundrops, Oenothera pumila.=

8b. Petals 14 mm. long or more =Sundrops, Oenothera fruticosa.=

9a. Petals 2, reverse heart-shape, stamens 2 (flowers small, white, summer) (Enchanter's Nightshade) --10.

9b. Petals 4; stamens 4 or 8 --12.

10a. Leaves rounded at the base, denticulate (3-8 dm. high; fruit p.r.i.c.kly) =Enchanter's Nightshade, Circaea lutetiana.=

10b. Leaves cordate at the base --11.

11a. Fruit 2-celled, bristly (2-4 dm. high) =Enchanter's Nightshade, Circaea intermedia.=

11b. Fruit 1-celled, with soft hairs (delicate plant 2 dm. high, or less) =Enchanter's Nightshade, Circaea alpina.=

12a. Petals entire (summer) --13.

12b. Petals notched at the end (flowers white or pinkish, less than 1 cm. broad, in summer) (Willow Herb) --15.

13a. Flowers 2-3 cm. wide, purple (7-20 dm. high) =Fireweed, Epilobium angustifolium.=

13b. Flowers about 1 cm. wide --14.

14a. Flowers red (2-5 dm. high) =Gaura, Gaura coccinea.=

14b. Flowers white, turning pink when old =Gaura, Gaura biennis.=

15a. Leaves entire, the margins usually somewhat revolute --16.

15b. Leaves toothed, flat (4-9 dm. high) --18.

16a. Plant densely p.u.b.escent with spreading hairs (3-8 dm. high) =Willow Herb, Epilobium molle.=

16b. Plant p.u.b.escent with appressed or incurved hairs --17.

17a. Leaves linear, the margin revolute (3-5 dm. high) =Willow Herb, Epilobium densum.=