Plant Field Guide

Figure 1: Diagram of Horsetail

Common Horsetail (Field Horsetail)

Equisetum arvense

This is the most prevalent plant in my observation area. The fertile stalks have brown and green bulbous stripes, are unbranched, and have a spore cone (about 2 inches long) at the top (see Figure 1). The fertile stalks are found during early spring, wilt, and give way to sterile stalks. The sterile stalks have branches that come in a green, whorled pattern. These branches are also jointed (see Figure 2 for comparison between fertile and sterile stalks). There are fields of these stalks along the edge of Lake Washington (see Figure 3). Often I have seen small birds, such as Savannah Sparrow hopping through when they are foraging for food.

Figure 2: Comparison of Fertile (Left) and Sterile Stalks (Right)

Figure 3: Field of Horsetails

Pacific Willow

Salix lucida (lasiandra)

Unlike other willows which are difficult to ID, the leaves of the Pacific Willow are not hairy. It also has a very signature yellow-orange bark. The twigs have an alternate growth pattern. The leaves are finely toothed, lanceolate, and grow in a whorled pattern. These willows have yellow catkins, which are produced in later spring. The twigs of the willow often grow in clusters. The Pacific Willow grows along the banks of Lake Washington as well as the small ponds that are found in the Union Bay Natural Area.

Black Cottonwood

Populus trichocarpa

This deciduous broadleaf tree grows well in riparian zones and has a signature leaf shape. Its soft leaves are a cordate leaf shape with an acute tip and have a finely toothed leaf margin. The leaf veins are fairly pronounced (fairly strong venation). The twigs are an alternate pattern with many bud scars. The petiole is a reddish color. The seeds of this tree are cottony. The bark is a gray color and marked with lenticels. These trees grow right in the middle of the Common Horsetail fields, which is often next to ponds and lakes. The Black Cottonwood trees in my observation site are often a good perch for birds such as the American Robin and White-Crowned Sparrow. The trees are also a victim of English Ivy.

Tall Oregon Grape

Mahonia aquifolium

One of two species of Oregon Grape, the Tall Oregon Grape can be identified by its ridged veins. This is apparent when you turn over the leaf (Figure 1). The Dwarf Oregon Grape (its counterpart) has smoothed veins. In addition, Tall Oregon Grapes have less than nine leaves per leaflet whereas the Dwarf Oregon Grape has greater than nine leaves per leaflet. This shrub has small, yellow flowers that grow in clusters. Its leaves are pinnately compound and spiny-edged (resemble Holly leaves). The leaves are elliptical and have a very glossy, green color. The bark is a light brown color. This flower is Oregon’s state flower, but it’s carefully tucked away in many thickets at the base of large trees at UBNA.

Figure 1: Ridged veins

Pacific Crabapple

Malus fusca

This small tree has white flowers that are about ¾ inch wide and have five rounded petals. The tree I was observing bloomed in the first week of April and since then has shed all of its petals. The flowers are found in clusters on the tree. The leaves of this tree are about three inches long, oblong, saw-toothed, slightly curled, and have an acute tip.  On the petiole (at the base of the leaf) there are two small, red knobs. The leaves seem to grow in clusters out of a hairy sheath. For this reason, I am a little unsure about the ID of the plant, so I am waiting to confirm its ID by fruit.

Broadleaf Cattail

Typha latifolia

A good indicator of wetlands, the cattails are very prevalent in the UBNA. The broad leaves are sheathed and are about as tall as the stems. The cattails are over five feet tall. Currently, the cattails at UBNA are withered with light brown papery leaves, but normally can be identified with green leaves. The flower is the most signature part of the plant (hence the name, cattail), which is composed of a dense collection of minute flowers. The male part is lighter brown and on top. It is the fluffy or withered component. The female part is a cylindrical shape, darker brown, and underneath the male part. These cattails are home to many birds including the Great Blue Heron and the male parts are a good perching location for birds including the Red-Winged Blackbird.

Himalaya Blackberry

Rubus armeniacus

Native to Armenia and Northern Iran, this invasive plant can be a bane in the Pacific Northwest. It grows in thickets that can vary greatly in size. The thickets in UBNA can vary from a whole edge of the lake to a small area around the trunk of a tree. The leaves are palmately compound with five fine toothed leaves per leaflet. The leaves are soft and papery and look very wrinkled. The color of the leaves also varies the whole spectrum of green. It looks like the older the leaf, the darker the green color. The stems are very prickly and clustered white flowers will bloom in early summer. This will produce red and black fruits. While this is an invasive plant, it is actually home to smaller birds as it offers protection with its prickly stems.

Snowberry

Symphoricarpos albus

This small shrub has leaves that are about ½-1 inch long. Its petite leaves have very irregular lobes and is elliptical when aged. The leaves can be described to have a mitten shape with one larger lobe and a smaller lobe attached. When young, the leaves are often circular shaped. The leaves are opposite and have a reddish color on the leaf margin. The red color is more pronounced when the leaf is turned over and the leaf veins are also a red color. The twigs of the snowberry are also a red color and very thin. The snowberry will produce clusters of white berries. The snowberry shrubs in UBNA are often tucked away underneath larger thickets and shrubs.