Field Guide to the Plants

Douglas Fir
Pseudotsuga menziesii 

This is the most common conifer in Madrona Woods. These are easily the largest and tallest trees in the park, with long straight trunks and scraggly branches in the canopy. If the twigs fall to the ground, you'll notice that the needles spiral around the twig (see Figure 1) when it is viewed end-on.

Figure 1 (leaves)

There are several trees in the park that are beginning to take on old growth characteristics in their bark and upper branches. Notice the armored appearance of these older trees (Figure 2). Although you need to look upward to see the large thick old branches that leave the tree in a haphazard fashion, if you look carefully, you can see one tree in the southwest quadrant of the park where bald eagles are balancing a nest in the upper branches. Finally, you Douglas fir has the most unique cones of any conifer in this region. Note the three-pointed bracts that are inter-leaved with the scales of the cone. If you use your imagination, they look like the hind-end of a mouse sticking out of the cone!

Figure 2 (bark)

Figure 3 (cones, note the unique 3-pointed bracts)

Dull Oregon Grape, Dwarf Oregon Grape
Mahonia nervosa

There are two Oregon grape species in the Madrona Woods. They both have compound leaves with spiny leaflets. They are both found in the understory of the park, especially under conifers in the uphill section of the park. Mahonia nervosa is usually shorter than its cousin, Mahonia aquifolium aka the tall Oregon grape, but a better way to identify it is by counting leaflets. Nervosa has 9 to 19 leaflets (see below). The underside of nervosa leaves have a network of veins emanating from a single point near the petiole. An infusion of the root of this species was used to treat rheumatism.

Tall Oregon Grape
Mahonia aquifolium

This species is perhaps most easily identified by its 5-9 shiny leaflets per compound leaf. It is often taller than its cousin, nervosa, but don't use size to identify it. Both species have yellow flowers and purple berries. The berries can be made into jam, but are better mixed with something tastier. Tall Oregon grape is recognized for its anti-bacterial properties when used topically. The leathery leaves of both the tall and the dull Oregon grape make both species very drought resistant. Tall Oregon grape is often used in landscaping in the Pacific Northwest.

To be continued: Remember, your goal for this week is to describe 8 species as I have done here.