Plants keep secrets, and holiday houseplants are no exceptions. Take the beautiful red flowers of the poinsettia plant, for example. Those are not flowers at all. And mistletoe? It takes advantage of others. Christmas cactus have a little something in common with mistletoe. Plus these plants often live under assumed names. Uncovering these and other plant mysteries is possible, with just a little bit of botany.
Poinsettias were used in dye making. The plant parts used to create reddish dye are often called flowers. But, the botanical secret of poinsettias is these plant parts are not flowers at all. They are bracts, or modified leaves.
The bracts form circles which look like blossoms, but the plant’s true flowers lie at the center of those circles. There, grouped together, are small, greenish flowers. The flowers lack petals and are either male, staminate, or female, pistillate. The flower groupings have a botanical name, cyathium or pseudanthium.
At this point, I should mention another well-kept poinsettia secret. Not all have red modified leaves. Some have pink, white or green bracts.
On to mistletoe. This plant is, at best, a halftime parasite. The botanical secret of mistletoe is their specialized roots. These roots penetrate other plants and steal nutrients! Some types of mistletoe survive solely off stolen goods.
Other types have the ability to photosynthesize, or create sugar from the sun’s energy. These mistletoe are only part-time parasites, or hemiparasites. Their ability to photosynthesize makes them green, and green mistletoe are what people use to steal kisses with during the holiday season.
By the way, proper mistletoe etiquette is that a berry is removed from the hanging plant after each kiss. When the berries are all gone, so should be the kisses.
Christmas cactus appear innocent. But, they are like mistletoe in that they live in other plants. Instead of stealing, they loiter. They use the host plant as a substrate, or as if it were soil. This mooch of a plant keeps another secret too. Its name.
Most Christmas cactus are actually Thanksgiving cactus. This is because Christmas cactus are not yet blooming when the holiday shopping season begins, but Thanksgiving cactus are. And so, retailers put the blooming plants out, knowing holiday shoppers are more likely to buy a plant with flowers than without.
To find out if your cactus is a Christmas cactus in name only, give it the botanical third degree. If its segments have rounded or scalloped edges and its flowers have radial symmetry, or look the same all around, you have a true Christmas cactus.
Under your interrogation, the Thanksgiving cactus will not be able to hide its segments’ pointy edges and its bilaterally symmetrical flowers. Thanksgiving cactus flowers will look the same when folded in half horizontally or vertically, but will not match if folded diagonally.
Rarely, an Easter cactus will be unmasked. They have large, wide segments and star-shaped blooms.
Now that you have used botany to uncover a few poinsettia, mistletoe and Christmas cactus secrets, you can enjoy a more informed holiday houseplant season.
Ashley Andrews is the horticulture communications assistant with University of Nevada Cooperative Extension. Horticulture questions? Contact 775-336-0265 or firstname.lastname@example.org, or visit growyourownnevada.com.