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As Sara pointed out, our mystery seeds from last week were from a shagbark hickory, Carya ovata.

Shagbark hickory trees are found growing naturally throughout the eastern United States.

Shagbark hickories are easy to identify because, as their name suggests, the trees have bark that peels off in patches.

Even relatively small trees exhibit this trait.

The leaves are pinnate, with five leaflets.

They turn a lovely yellow color in the fall.

Here is a short video that gives more details about how to identify a shagbark hickory.

As the video mentions, the hickory is prized for its wood.

The nuts are found in a thick husk, which opens as they ripen. Although the "nutmeats" inside are fully edible, the shells of the nut are tough and it is hard to remove the seeds inside. That is probably why shagbark hickories aren't grown for commercial production like their cousin the pecan, Carya illinoensis. If you work at it, however, the resulting nuts are worth the extra effort. Hickory nut cakes and pies are delicious!

People also make shagbark hickory syrup. Apparently the syrup is made from the bark rather than the sap, at least according to some websites like this one:  Making Shagbark Hickory Syrup.

Have you ever eaten hickory nuts or hickory syrup? Do you have a favorite recipe?


Our mystery seeds from last week came from the ironwood tree, Olneya tesota.

This unique tree gets its common name from the extreme hardness of its wood. Because there are a number of other trees with the same common name, it is sometimes called desert ironwood.

Desert ironwood is a small, shrubby tree found throughout the Sonoran Desert. The lower branches droop, giving a lovely form in its natural state.

The bark of the younger trunks and branches are pale gray to green at the tips.

It is a legume, having compound leaves of narrow, elliptical leaflets.

As with many desert plants, it is well armed, with many pairs of curved spines.

Desert ironwoods produce many lovely purplish-pink flowers in the spring. See Firefly Forest for a photograph of ironwood flowers.

The seed pods mature on the plant and then fall off.

The clue I mentioned that you might have noticed in the the mystery seed photograph last week was a drying leaf toward the bottom of the shot.

You can grow new trees from these seeds, but people often chose to purchase larger trees because desert ironwoods are very slow growing.

If you travel through the low desert you will often see dead ironwood trees. That is because the wood contains strong chemicals that prevent decay after the tree has died and the wood remains in place, sometimes for hundreds of years.

For more detail, see Natural History of the Desert Ironwood Tree (Olneya tesota) from the Arizona-Sonora Desert Museum.

Our mystery seeds from last week were from a blue palo verde, Parkinsonia florida (previously Cercidium floridum).

The blue palo verde is unique to the Southwest and is the Arizona State Tree.

Palo verdes are small trees named for their green trunk and branches.

Why green? The top layer of the trunk and branches contains chlorophyll, which allow the tree to continue to make food via photosynthesis even if it doesn't have leaves.

A close up of the trunk...

Blue palo verdes do have leaves at certain times of the year, but they tend to be small and fall off when the plant is under water stress.

Often the trees are covered with brilliant yellow blossoms in the spring...

...which produce these seed pods full of seeds.

In addition to the blue palo verde, several other species of palo verdes grow in Arizona, including the foothills palo verde, Parkinsonia microphylla and the Mexican palo verde, Parkinsonia aculeata.

The flowers of the Mexican palo verde are unusual because the top petal changes color with age, until it is a deep reddish orange.

Firefly Forest has more photographs and facts about Mexican palo verdes, blue palo verdes, and foothills palo verde.

Desert Harvesters has information about how to identify blue and foothills palo verde trees, plus tips for harvesting the pods