b. Fruit light red, cl.u.s.tered, July-August; twigs usually less than 1/16 inch thick; pith of twigs brown; tree northern. _P.

pennsylvanica_, p. 139.

bb. Fruit black, racemose, August-September; twigs usually more than 1/16 inch thick; pith of twigs white; tree southern. _P.

serotina_, p. 155.

+WINTER KEY TO THE SPECIES OF PRUNUS+

a. Terminal bud present; bark of young trunks rather smooth.

b. Buds cl.u.s.tered at the tips of all shoots; twigs usually less than 1/16 inch thick; pith of twigs brown. _P. pennsylvanica_, p. 159.

bb. Buds not cl.u.s.tered, or cl.u.s.tered only on short, spur-like branchlets; twigs usually more than 1/16 inch thick; pith of twigs white.

c. Buds usually 1/4 inch or less in length; bud-scales uniform in color, apiculate at the apex; bark on old trunks blackish, rough-scaly; small to large tree. _P. serotina_, p. 155.

cc. Buds usually 1/4-1/2 inch long; bud-scales grayish on the margins, rounded at the apex; bark on old trunks brown, smooth or only slightly fissured; usually a large shrub. _P.

virginiana_, p. 157.

aa. Terminal bud absent; bark of young trunks early splitting off in large, thick plates. _P. nigra_, p. 161.

[Ill.u.s.tration: +Black Cherry+

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 3/4.

4. Margin of leaf, enlarged.

5. Flowering branchlet, 1/2.

6. Vertical section of flower, enlarged.

7. Fruiting branchlet, 1/2.]

+ROSACEAE+

+Black Cherry+

_Prunus serotina Ehrh._ [_Padus serotina (Ehrh.) Agardh._]

HABIT.--A medium-sized tree 40-50 feet high and 8-36 inches in trunk diameter; branches few, large, tortuous, forming a rather spreading, oblong or rounded crown.

LEAVES.--Alternate, simple, 2-5 inches long, about one-half as broad; oval or oblong to oblong-lanceolate; finely serrate, with teeth incurved; subcoriaceous; dark green and very l.u.s.trous above, paler beneath, glabrous both sides; petioles short, slender, usually bearing 2 red glands near the blade.

FLOWERS.--May-June, when the leaves are half grown; perfect; 1/4 inch across; borne on slender pedicels in many-flowered, loose racemes 4-5 inches long; calyx cup-shaped, 5-lobed; petals 5, white; stamens 15-20; stigma thick, club-shaped.

FRUIT.--August-September; a globular drupe, 1/3-1/2 inch in diameter, nearly black, with dark purple, juicy flesh; slightly bitter, edible.

WINTER-BUDS.--Terminal bud about 1/4 inch long, ovoid, blunt to acute; scales keeled on the back, apiculate, light brown.

BARK.--Twigs and branches red to red-brown; young trunks dark red-brown, smooth; blackish on old trunks and rough, broken into thick, irregular plates; bitter, aromatic.

WOOD.--Light, rather hard, strong, close- and straight-grained, light brown or red, with thin, yellow sapwood.

DISTRIBUTION.--Frequent in the southern half of the Lower Peninsula, rare in the northern half and the Upper Peninsula.

HABITAT.--Prefers a rich, moist soil, but grows well on dry, gravelly or sandy soils.

NOTES.--Grows very rapidly in youth.

[Ill.u.s.tration: +Choke Cherry+

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 1.

4. Margin of leaf, enlarged.

5. Flowering branchlet, 1/2.

6. Vertical section of flower, enlarged.

7. Fruit, 1/2.]

+ROSACEAE+

+Choke Cherry+

_Prunus virginiana L._ [_Padus virginiana (L.) Roemer_]

HABIT.--Usually a large shrub, but sometimes a small tree 15-25 feet high, with a crooked, often leaning trunk 5-6 inches in diameter; forming a spreading, somewhat rounded crown.

LEAVES.--Alternate, simple, 2-4 inches long, one-half as broad; obovate to oblong-obovate or oval, abruptly ac.u.minate at the apex; finely and sharply serrate; dull dark green above, paler beneath, glabrous both sides; petioles short, slender, glandular at the apex.

FLOWERS.--May, when the leaves are half grown; perfect; about 1/2 inch across; borne on short, slender pedicels in many-flowered racemes 3-6 inches long; calyx cup-shaped, 5-lobed; petals 5, white; stamens 15-20; stigma broad, on a short style.

FRUIT.--July-August; a globular drupe, 1/4-1/2 inch in diameter, usually bright red, often yellow to almost black, with dark red flesh; astringent, but edible.

WINTER-BUDS.--Terminal bud 1/4-1/2 inch long, conical, acute; scales rounded at the apex, light brown, smooth.

BARK.--Twigs at first light brown or greenish, becoming red-brown, finally dark brown; thin, dark brown on the trunk, slightly fissured.

WOOD.--Heavy, hard, close-grained, weak, light brown, with thick, lighter colored sapwood.

DISTRIBUTION.--Common throughout the entire state.

HABITAT.--Prefers a deep, rich, moist loam, but is common on less favorable sites.

NOTES.--The most widely distributed tree of North America, extending from the arctic circle to Mexico, from the Rocky Mountains to the Atlantic Ocean.