Monday, June 7, 2010

Crataegus laevigata - English Hawthorn

Crataegus laevigata: Crataegus is the Greek name for this genus of trees. Derives from kratos meaning strength, referring to hardness of wood; laevigatais Latin meaning 'having a smooth or slippery surface.'

Previously known as C. oxyacantha from the Greek ‘oxus’ meaning sharp and ‘akantha’ meaning thorn.

Small stature tree from Europe. Greeks and Romans associated Hawthorne with marriage and fertility.

The straight species has white hermaphroditic flowers with a single whorl of petals in terminal corymbs. Flowers appear in spring and attract bees.

Cultivars with pink to red double and single flowers are common.

Clusters of small red, fleshy, pome fruits contain 1-5 seeds and are persistent through winter, attracting birds. Fruit is larger and purer red than C. phaenopyrum. Hawthorne Berries have been used since the nineteenth century to support the heart and to normalize cardiovascular functions.

Linnaeus' original description of C. oxyacantha was later disambiguated into C. monogyna (left) and C. laevigata (right), the main difference being the depth of the sinuses between lobes. C. laevigata also has rounder lobes and serrate margins, whereas C. monogyna can have entire margins or points just at the tips of lobes.

Branches have sharp 1" spines. The branches of this tree are said to have furnished Christ's crown of thorns.

Bark is reddish brown to gray and becomes scaly or peels in thin narrow strips with age.

Sunday, June 6, 2010

Betula papyrifera - Canoe Birch or Paper Birch

Betula papyrifera: Betula is Latin for birch; papyrifera from the Greek word 'papurus,' meaning 'papyrus' or 'paper' and the Latin word 'fero' meaning 'to bear, carry, bring'. Taken together, papyrifera means "paper bearing," for the tree's paper-like bark.

Native American tribes often used this tree to make canoes due to its waterproof bark. The bark can also be used to create a durable, waterproof layer in constructing sod-roofed houses.

Native to the north east United States and Canada. Branches are only slightly more upright than B. pendula. This species will naturally hybridize with almost any other native birch.

Leaves alternate, 1-3" long with doubly serrate margins. Often unequally cordate at the base. Upper surface glabrous, minutely hairy underneath. Fall color is yellow.

Pendulous male catkins 4" long in clusters of 1-3 in late winter to early spring. Female fruiting catkins (not pictured) 1" long occur at the ends of branches. Trees are monoecious.

Smooth, thin white bark with horizontal orange lenticels peels off in large papery sections. Young twigs are a shiny orange-brown. Compare to B. pendula whose bark cracks with maturity, revealing dark brown to black bark underneath.

White trunks create a striking winter silhouette.

Saturday, June 5, 2010

Araucaria auracana - Monkey Puzzle Tree

Araucaria araucana: Genus and species named for Arauco Indians of Chile and Argentina, who have natural forests of this tree and harvest the seeds for food.

Curious looking tree similar to A. bidwillii.

Awl-shaped leaves 1-2" long, dark green, whorled around the branch.

Trees are dioecious -- male and female cones appear on separate trees.

4-7" female cones are solitary at the ends of branchs and take 2-3 years to ripen.

Bark is reddish to grey-brown with shallow seams and rings from old branch scars.

Trunk appears wrinkley with age.

This is the most hardy of the araucarias. They are also drought tolerant and disease resistant.

Friday, June 4, 2010

Acer saccharinum - Silver Maple

Acer saccharinum: Acer is the Latin name for maples; saccharinum refers to the tree's sweet sap. This species yields about half the amount of sugar as A. saccharum.

Native to wet floodplain forests in the Eastern United States.

Deeply 5-lobed leaves with sharply serrate margins are dark green on top, but silvery grey underneath, giving the tree its common name.

Yellow to orange to red fall color, often seen all together.

Tiny corymbs of red polygamous, apetalous flowers in late winter (~March) before the tree leafs out.

Samaras with twin seeds are joined at almost 180ยบ. Fruit matures in late spring and persists through the summer.

Bark is light silver-grey, turning darker grey with maturity with narrow fissures and scaly plates.