14a. The pair of spines at the base of each leaf straight or nearly so =Wild Rose, Rosa humilis.=

14b. The pair of spines at the base of each leaf distinctly recurved or hooked --15.

15a. Leaves densely glandular-p.u.b.escent beneath =Sweetbrier, Rosa rubiginosa.=

15b. Leaves glabrous or minutely p.u.b.escent =Swamp Rose, Rosa carolina.=

16a. Stems trailing or creeping --17.

16b. Stems erect, ascending, or arched --19.

17a. Stems distinctly shrubby and th.o.r.n.y (Dewberry) --18.

17b. Stems almost herbaceous, without thorns =Dwarf Raspberry, Rubus triflorus.=

18a. Leaves thin, dull above; fruit black, large and juicy =Dewberry, Rubus villosus.=

18b. Leaves firm or thick, shining above; fruit reddish, small, consisting of a few sour drupelets =Swamp Dewberry, Rubus hispidus.=

19a. Ripe fruit dropping away from the white receptacle or core; terminal leaflet of each leaf with a long stalk, while the lateral leaflets are sessile or nearly so (Raspberry) --20.

19b. Ripe fruit and receptacle or core dropping together; all the leaflets on stalks which are approximately equal in length (Blackberry) --22.

20a. Stem very glaucous with a whitish or bluish waxy deposit; fruit black =Black Raspberry, Rubus occidentalis.=

20b. Stem not glaucous; fruit red --21.

21a. Calyx velvety-p.u.b.escent =Red Raspberry, Rubus idaeus.=

21b. Calyx bristly-hispid =Red Raspberry, Rubus idaeus var. aculeatissimus.=

22a. Pedicels with gland-tipped hairs, but no p.r.i.c.kles =Blackberry, Rubus allegheniensis.=

22b. Pedicels with p.r.i.c.kles =Blackberry, Rubus nigricans.=

22c. Pedicels with neither p.r.i.c.kles nor gland-tipped hairs --23.

23a. Leaves downy beneath =Blackberry, Rubus frondosus.=

23b. Leaves smooth beneath =Blackberry, Rubus canadensis.=

24a. Ovaries 1 or more, superior (attached to the surface of the receptacle, but not concealed within it or united to it) --25.

24b. Ovary 1, inferior (permanently enclosed within the receptacle, with only the styles protruding) --38.

25a. Ovaries more than 1 --26.

25b. Ovary 1 --30.

26a. Leaves serrate --27.

26b. Leaves lobed --28.

27a. Leaves glabrous or very nearly so (8-20 dm. high; flowers white or pinkish, summer) =Meadow-sweet, Spiraea salicifolia.=

27b. Leaves closely p.u.b.escent beneath (5-15 dm. high; flowers pink, summer) =Hardhack, Spiraea tomentosa.=

28a. Flowers showy, purple or white, 3-4 cm. broad --29.

28b. Flowers white, about 1 cm. wide (1-3 m. high; flowers in early summer) =Ninebark, Physocarpus opulifolius.=

29a. Flowers purple =Flowering Raspberry, Rubus odoratus.=

29b. Flowers white =Salmonberry, Rubus parviflorus.=

30a. Flowers in racemes (trees or tall shrubs; flowers white, in late spring) --31.

30b. Flowers in small umbels or corymbs (flowers white, in spring) --32.

31a. Leaves oblong, the points of their teeth incurved =Black Cherry, Prunus serotina.=

31b. Leaves obovate, the points of their teeth spreading =Choke Cherry, Prunus virginiana.=

32a. Flowers about 1 cm. wide --33.

32b. Flowers about 1.5-2.5 cm. wide --36.

33a. Low shrubs, with the spatulate or oblong leaves widest above the middle --34.

33b. Erect tall shrubs or small trees, with the leaves widest below the middle --35.

34a. An erect shrub (5-10 dm. high) =Appalachian Cherry, Prunus cuneata.=

34b. A prostrate or ascending shrub (3-15 dm. high) =Sand Cherry, Prunus pumila.=

35a. Leaves very broadly ovate, almost as wide as long (small tree) =Perfumed Cherry, Prunus mahaleb.=

35b. Leaves oblong-lanceolate, about 3 times as long as broad (shrub or small tree, 2-10 m. high) =Pin Cherry, Prunus pennsylvanica.=

36a. Sepals glandular-serrate (tall shrub or small tree) =Wild Plum, Prunus nigra.=

36b. Sepals entire --37.

37a. Leaves with sharp teeth, frequently bristle-tipped; a native species (tall shrub or small tree, frequently growing in thickets) =Wild Plum, Prunus americana.=

37b. Leaves with obtuse teeth; a species escaped from cultivation (widely branched tree) =Cherry, Prunus cerasus.=

38a. Trees, in cultivation or escaped from cultivation near roads or dwellings, with showy flowers 2.5-5 cm. across, edible fruits, and no thorns (spring) --39.