25b. All flowers of the cl.u.s.ter alike --26.

26a. Leaves finely serrate; the veins not prominent --27.

26b. Leaves coa.r.s.ely serrate, all or most of the teeth terminating in a prominent vein --29.

27a. Peduncle of the flower-cl.u.s.ter, below its branches, at least 2 cm.

long (1-3 m. high) =Withe-rod, Viburnum ca.s.sinoides.=

27b. Peduncle of the cl.u.s.ter 1 cm. long, or even shorter (3-8 m. high) --28.

28a. Leaves distinctly ac.u.minate =Sheep-berry, Viburnum lentago.=

28b. Leaves obtuse or barely acute =Black Haw, Viburnum prunifolium.=

29a. Leaves densely p.u.b.escent beneath (6-15 dm. high) =Arrow-wood, Viburnum p.u.b.escens.=

29b. Leaves glabrous beneath, or with tufts of hairs in the forks of the veins (1-4 m. high) =Arrow-wood, Viburnum dentatum.=

VALERIANACEAE, the Valerian Family

Herbs with opposite leaves and small nearly or quite regular flowers; petals 5, united; stamens 3; sepals minute or wanting; ovary inferior.

1a. Stem-leaves pinnately cleft (3-10 dm. high; flowers white or pinkish, summer) --2.

1b. Stem-leaves entire or dentate (2-6 dm. high; flowers white, summer) (Corn Salad) --3.

2a. Leaf-segments parallel-veined Valerian, Valeriana edulis.

2b. Leaf-segments net-veined =Swamp Valerian, Valeriana uliginosa.=

3a. Upper stem-leaves entire =Corn Salad, Valerianella chenopodifolia.=

3b. Upper stem-leaves dentate =Corn Salad, Valerianella radiata.=

DIPSACACEAE, the Teasel Family

Herbs with opposite leaves, and small pale blue flowers aggregated in dense heads; calyx minute; petals 4, united; stamens 4, attached to the corolla; ovary inferior.

One species in Michigan, 1-2 m. high, with p.r.i.c.kly leaves and stem, blooming in summer =Teasel, Dipsacus sylvestris.=

CUCURBITACEAE, the Gourd Family

Herbs, climbing by tendrils, with alternate palmately lobed leaves and imperfect flowers; staminate flowers in showy cl.u.s.ters, with 5-6 petals and 3 stamens; pistillate flowers small.

1a. Leaves 5-angled or shallowy 5-lobed (flowers white, summer) =Bur Cuc.u.mber, Sicyos angulatus.=

1b. Leaves 5-lobed to about the middle (commonly cultivated and frequently wild; flowers white, summer) =Wild Cuc.u.mber, Echinocystis lobata.=

CAMPANULACEAE, the Bellflower Family

Herbs with alternate simple leaves and milky juice; sepals 5; petals 5, united; stamens 5, attached at the very base of the corolla; ovary inferior.

1a. Stem-leaves circular or nearly so, cordate-clasping at base (2-6 dm.

high; flowers blue, axillary, in summer) =Venus' Looking-Gla.s.s, Specularia perfoliata.=

1b. Stem-leaves linear or nearly so, not over 1 cm. wide (summer) --2.

1c. Stem-leaves ovate to lanceolate, 2 cm. wide or more (flowers blue, in a terminal spike or raceme, summer) (Bellflower) --4.

2a. Stem and leaves glabrous (or rarely p.u.b.escent) (1-6 dm. high; flowers blue) =Harebell, Campanula rotundifolia.=

2b. Stem and leaves rough with reflexed bristles (marsh plants, with weak slender stems 3-10 dm. long; flowers white or pale-blue) (Marsh Bellflower) --3.

3a. Corolla 5-8 mm. long =Marsh Bellflower, Campanula aparinoides.=

3b. Corolla 10-12 mm. long =Marsh Bellflower, Campanula uliginosa.=

4a. Corolla rotate; flowers in spikes (6-15 dm. high) =Bellflower, Campanula americana.=

4b. Corolla bell-shape; flowers in one-sided racemes (4-10 dm.

high) =Bellflower, Campanula rapunculoides.=

LOBELIACEAE, the Lobelia Family

Herbs with alternate simple leaves and milky juice; flowers irregular; petals 5, united; corolla split down the upper side; stamens 5, united by their anthers into a ring or tube surrounding the style; ovary 2-celled, inferior. Flowers in summer and autumn.

1a. Leaves all basal, tubular; flowers on leafless stalks (aquatic, 1-4 dm. high; flowers blue) =Water Lobelia, Lobelia dortmanna.=

1b. Leaves normal, on the stem --2.