The Plants of Michigan Part 50

21b. Flowers irregular, the calyx oblique, longer on the upper side than on the lower --22.

22a. Stamens projecting beyond the calyx =Alum Root, Heuchera hirsuticaulis.=

22b. Stamens not projecting beyond the calyx =Alum Root, Heuchera hispida.=

23a. Stem-leaves alternate or none --24.

23b. Stem with a pair of opposite leaves (2-4 dm. high) =Bishop's Cap, Mitella diphylla.=

24a. Petals deeply fringed (1-2 dm. high) =Bishop's Cap, Mitella nuda.=

24b. Petals entire (1-3 dm. high) =False Mitrewort, Tiarella cordifolia.=

HAMAMELIDACEAE, the Witch Hazel Family

Shrubs, with alternate simple leaves; sepals, petals, and stamens each 4; ovary 2-lobed.

One species in Michigan; tall shrub with obovate leaves and yellow flowers appearing late in autumn =Witch Hazel, Hamamelis virginiana.=

PLATANACEAE, the Plane Tree Family

Trees, with broad, palmately veined and lobed leaves, and minute flowers in dense spherical heads.

One species in Michigan =Sycamore, Plata.n.u.s occidentalis.=

ROSACEAE, the Rose Family

Trees, herbs, or shrubs, with alternate, frequently compound leaves; petals and sepals usually 5, stamens numerous, pistils 1 to many; receptacle expanded into a saucer-shape or cup-shape organ, bearing the sepals, petals, and stamens at its margin, the pistils at its center, and resembling a calyx-tube or flattened calyx.

1a. Shrubs or trees --2.

1b. Herbaceous plants --48.

2a. Leaves compound --3.

2b. Leaves simple --24.

3a. Flowers in large panicles or corymbs, each flower 5-10 mm. across; leaflets 7 or more --4.

3b. Flowers solitary or in small cl.u.s.ters, each flower usually 20-80 mm.

wide; leaflets frequently only 3 or 5 --7.

4a. Flowers in a pyramidal or oblong panicle, the ovaries superior (1-2 m. high; flowers white, in summer) --70b.

4b. Flowers in rounded or hemispheric cl.u.s.ters, the ovary inferior --5.

5a. Leaves p.u.b.escent on the lower surface =Rowan Tree, Pyrus aucuparia.=

5b. Leaves glabrous beneath when mature (small trees; flowers white, in early summer or late spring) (Mountain Ash) --6.

6a. Leaves ac.u.minate at the apex =Mountain Ash, Pyrus americana.=

6b. Leaves obtuse or acute at the apex =Mountain Ash, Pyrus sitchensis.=

7a. Flowers yellow (5-10 dm. high; summer) =Cinquefoil, Potentilla fruticosa.=

7b. Flowers pink or red, rarely white, 4-10 cm. across (shrubs, 5-15 dm.

high, or climbing; stems usually th.o.r.n.y; flowers in early summer) (Rose) --8.

7c. Flowers white, 1-3 cm. across (4-20 dm. high; flowers in late spring) --16.

8a. Leaflets on most of the leaves 3; styles cohering in a column which protrudes from among the stamens =Climbing Rose, Rosa setigera.=

8b. Leaflets 5-11; styles not cohering in a protruding column --9.

9a. Sepals persistent on the fruit after flowering --10.

9b. Sepals soon deciduous from the young fruit after flowering --14.

10a. A pair of spines below each leaf larger than the other spines --11.

10b. Spines all alike in size or nearly so, or absent completely --12.

11a. Sepals entire =Wild Rose, Rosa woodsii.=

11b. Sepals pinnatifid =Dog Rose, Rosa canina.=

12a. Stems with few thorns or none at all =Wild Rose, Rosa blanda.=

12b. Stems p.r.i.c.kly --13.

13a. Fruit somewhat pear-shape, narrowed toward the base.

=Wild Rose, Rosa acicularis.=

13b. Fruit globose, rounded at the base =Wild Rose, Rosa acicularis var. bourgeauiana.=