Confused yet? 
Wander around the quintessential landscape of the American Southwest, and you will see the characteristic spiky century plants, of the genus Yucca (sounds like yuck-a). Lucky you! Beautiful to look at, pokey to touch, they are often used for their fiber, their beauty, and their edible flowers and stalk.
Wander into a restaurant or home of a chef specializing in South American cuisine, and you will encounter the delicious, starchy goodness that is yuca (sounds like yoo-ka). Again, lucky you! Fried yuca with a mystery green chili fresh cheese sauce, made by a Peruvian grandmother of my acquaintance, is a dish of memorable deliciousness.
But these things are not related! Once again vernacular has confused the issue. Yuca, delicious starchy root vegetable, is from the plant Manihot esculenta, also known as cassava, tapioca, or by any number of other names. This plant is well loved, a staple food for a significant portion of the globe, and so people like to give it names. It’s a very interesting plant, one that deserves future discussion. But not even closely related to charismatic Joshua Tree, Yucca brevifolia.
You’d think botanists would be a little more considerate of us non-botanical folks… I have a hard enough time keeping straight plants names that don’t sound even closely alike! Also, this jogged my memory on something a friend told me about a spiky, fibrous desert plant (that I know see is Yucca)… the spiky leaf tip and connected fibres can be used as a needle and thread in a bind. Plants are just too awesome, as you have aptly noted.
Anyways, thanks for saving me from making embarrassing mix-ups of Yucca, Yuca, and Yucca brevifolia at the watercooler.
On second thought, I bet botanists are not the ones to blame, as Yuca and Yucca are common names and not species names?
I think Kathy learned how to make the delicious green stuff.