It looks kind of like a brownish-green twig hidden in a bush or tree.
If you observe closely, you may see the spines that indicate it is a cactus. In fact, it is a cactus called Arizona Queen of the Night, Peniocereus greggii.
Once in a great while it will produce a flower or two. Then it will be obvious why people find it so interesting.
The brilliant white flowers stay open for only one night.
This one is already starting to close as the sunlight begins to find it, although it was still producing a heavy perfume. Many of the night blooming flowers here are white and produce a strong, sweet odor that attracts moths to pollinate them.
Hopefully this flower was pollinated and produces some more mystery seeds.
I started you with a tricky one, because it is only found in the desert. Common names for these plants are barrel cactus and fishhook cactus. The scientific name is Ferocactus.
The name fishhook cactus comes from the fish hook shape of the spines of certain species. I have read that the American Indians of some tribes did use them for fish hooks.
It is also called the compass cactus because in natural settings the shady side grows longer and the cactus tilts to the South.
The flowers are sources of nectar and pollen for bees.
The bright yellow fruit are supposedly eaten by deer and certain rodents.
For more about the special relationship between ants and barrel cacti, see my Wild About Ants blog.
This week's mystery seed:
The shiny, hard black seeds of the barrel cactus reminded me of the seeds of another plant in our yard. This time I'll give you a hint. The mystery seeds this week might be easier for our Australian friends to identify.
For a combined celebration of Earth Day and Arbor Day, my son and I went to the Desert Botanical Garden in Phoenix. A number of the cacti were in full bloom the day we went, the butterfly pavilion is open and Dale Chihuly's glass exhibit is in place. It was incredible.
I decided a blog post wouldn't do the photos justice, so I have posted them in a page that allows for a slide show. Follow the link and then click on "Play Slideshow."