Michigan Trees Part 11

+PINACEAE+

+Arborvitae. White Cedar+

_Thuja occidentalis L._

HABIT.--A tree 40-50 feet high, with a short, often b.u.t.tressed trunk 1-2 feet in diameter, often divided into 2-3 secondary stems; forming a rather dense, wide-based, pyramidal crown.

LEAVES.--Opposite, 4-ranked, scale-like, appressed; ovate, obtuse or pointed, keeled in the side pairs, flat in the others; 1/8-1/4 inch long; yellow-green, often becoming brown in winter; strongly aromatic when crushed. Persistent 1-2 years.

FLOWERS.--April-May; usually monoecious; the staminate minute, globose, yellow, composed of 4-6 stamens arranged oppositely on a short axis; the pistillate small, oblong, reddish, composed of 8-12 scales arranged oppositely on a short axis.

FRUIT.--Early autumn of first season, but persistent on the branch through the winter; erect, short-stalked, oblong-ovoid, pale brown cones, about 1/2 inch long, composed of 8-12 loose scales; seeds 1/8 inch long, ovate, acute, winged.

WINTER-BUDS.--Naked, minute.

BARK.--Twigs yellow-green, becoming light red, finally smooth, l.u.s.trous, dark orange-brown; thin, light red-brown on the trunk, slightly furrowed or deciduous in ragged strips.

WOOD.--Light, soft, brittle, rather coa.r.s.e-grained, durable, fragrant, pale yellow-brown, with thin, whitish sapwood.

DISTRIBUTION.--Throughout the Upper Peninsula, Lower Peninsula as far south as Montcalm County.

HABITAT.--Prefers moist soil in low swamps and along river-banks.

NOTES.--Slow of growth. Tolerant of all soils and exposures. Especially useful for hedges or narrow evergreen screens.

[Ill.u.s.tration: +Red Juniper. Red Cedar+

1. Branchlet with awl-shaped leaves, 1.

2. Tip of branchlet, showing awl-shaped leaves, enlarged.

3. Fruiting branchlet with scale-like leaves, 1.

4. Tip of branchlet, showing scale-like leaves, enlarged.]

+PINACEAE+

+Red Juniper. Red Cedar+

_Juniperus virginiana L._

HABIT.--A medium-sized tree 30-40 feet high, with a trunk diameter of 1-2 feet; forming an irregular, pyramidal or rounded crown.

LEAVES.--Opposite, of two kinds: (1) sessile, scale-like, closely appressed, overlapping, 4-ranked, ovate, acute, 1/16 inch long, (2) sessile, awl-shaped, loosely arranged, 1/4-1/2 inch long. Persistent 5-6 years.

FLOWERS.--May; usually dioecious; minute; the staminate oblong-ovoid, composed of 4-6 s.h.i.+eld-like scales, each bearing 4-5 yellow, globose pollen sacs; the pistillate ovoid, composed of about 3 pairs of flesh, bluish scales, united at the base and bearing 2 ovules.

FRUIT.--Autumn of first or second season; subglobose, berry-like strobile, about 1/4 inch in diameter, dark blue and glaucous; flesh sweet and resinous; seeds 2-3.

WINTER-BUDS.--Naked, minute.

BARK.--Twigs greenish to red-brown and smooth; thin, light red-brown on the trunk, exfoliating lengthwise into long, narrow, persistent strips, exposing the smooth, brown inner bark.

WOOD.--Light, soft, close-grained, brittle, weak, durable, very fragrant, dull red, with thin, whitish sapwood.

DISTRIBUTION.--Occurs sparingly throughout the state; most abundant in the southern portion.

HABITAT.--Prefers loamy soil on sunny slopes; dry, rocky hills; also borders of lakes and streams, peaty swamps.

NOTES.--Slow of growth. Long-lived. Should be transplanted with ball of earth. Tolerant of varied soils and situations.

+SUMMER KEY TO THE SPECIES OF SALIX+[D]

a. Leaf-petioles without glands.

b. Leaves 1/4-3/4 inch broad; petioles broad and flat. _S.

nigra_, p. 37.

bb. Leaves 3/4-1/4 inches broad; petioles slender and terete.

_S. amygdaloides_, p. 39.

aa. Leaf-petioles glandular above.

b. Leaves 1/4-1/2 inch broad, sharp-serrate; tree with weeping habit. _S. babylonica_, p. 43.

bb. Leaves 1/2-1-1/2 inches broad, blunt-serrate; tree with upright habit. _S. fragilis_, p. 41.

+WINTER KEY TO THE SPECIES OF SALIX+

The cla.s.sification of the Willows is a task for the specialist, even when leaves and both staminate and pistillate flowers are obtainable. It is impractible for the novice to attempt the determination of species of Salix with winter characters alone. Consequently the usual winter key is omitted.

+SALICACEAE+

+Willow+

_Salix (Tourn.) L._

The genus _Salix_ is represented in Michigan by thirty or more distinct species, and there are many more hybrids. The majority of these are shrubs, only a few becoming truly arborescent. Because of the similarity of their botanical characters, the frequency with which they hybridize, and the facility with which they respond to their environment only an expert is competent to identify the species so abundant along our water courses and on the banks of our lakes and swamps. The scope of this work being necessarily limited, it has been deemed best to describe but two of our native willows and two of our foreign neighbors which are frequently planted.

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

1. Winter twig, 1.

2. Portion of twig, enlarged.