20a. Flowers numerous in each axil =Indian Currant, Symphoricarpos orbiculatus.= 20b. Flowers 1 or 2 in each axil (Snowberry) --21. 21a. Leaves green beneath =Snowberry, Symphoricarpos racemosus.= 21b. Leaves whitened beneath =Snowberry, Symphoricarpos racemosus var. pauciflorus.= 22a. Leaves palmately lobed --23. 22b. Leaves not lobed --25. 23a. Outermost flowers of the cluster enlarged and imperfect (1-4 m. high) =Cranberry Tree, Viburnum opulus var. americanum.= 23b. All flowers of the cluster alike --24. 24a. Flower-clusters 4-10 cm. broad (1-2 m. high) =Arrow Wood, Viburnum acerifolium.= 24b. Flower-clusters 2-3 cm. broad =Squashberry, Viburnum pauciflorum.= 25a. Outer flowers of the cluster enlarged and imperfect (1-3 m. high) =Hobble-bush, Viburnum alnifolium.= 25b. All flowers of the cluster alike --26. 26a. Leaves finely serrate; the veins not prominent --27. 26b. Leaves coarsely serrate, all or most of the teeth terminating in a prominent vein --29. 27a. Peduncle of the flower-cluster, below its branches, at least 2 cm. long (1-3 m. high) =Withe-rod, Viburnum cassinoides.= 27b. Peduncle of the cluster 1 cm. long, or even shorter (3-8 m. high) --28. 28a. Leaves distinctly acuminate =Sheep-berry, Viburnum lentago.= 28b. Leaves obtuse or barely acute =Black Haw, Viburnum prunifolium.= 29a. Leaves densely pubescent beneath (6-15 dm. high) =Arrow-wood, Viburnum pubescens.= 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 prickly leaves and stem, blooming in summer =Teasel, Dipsacus sylvestris.=