[This is the first in a series of three posts; the second post is: Poinsettia flower closeups take two: getting even closer and the third is Poinsettia flowers part three: the female parts.]

Orange Coast College’s Ornamental Horticulture Department is just plain awesome. The department’s landscaped gardens are easily the most beautiful spot on campus, they teach a wide array of neat classes (landscape design, plant propagation, cacti and succulents, etc.), and they’ve got the nicest faculty and staff around.

To help fund their department, and provide a lab opportunity for their plant propagation class, every fall the department rears thousands of poinsettias (Euphorbia pulcherrima) in their greenhouses for sale to the public. This year’s sale is this Friday (December 9), and their greenhouses are currently full of beautiful poinsettias.

I just had to take a look at the plants last week:

Many people think that the big red (or red and white, in the picture above) structures are the flower petals of poinsettias; they’re not.  The big red structures are bracts: specialized leaves associated with a flower that are typically brightly colored (usually to help attract pollinators to inconspicuous flowers).  The actual flowers of the plant are located at the ends of the stems, and are significantly smaller and less noticeable.  Look closely at the picture above, though, and you’ll see little green, red, and yellow clusters at the top of the plant; those are the flowers.

In the picture above we can see that the true flowers of the poinsettia are not the brightly colored leaves, but instead are these small green and red structures. The yellow things that look like lips are nectar glands, and the green balls with red filaments are the flowers (which are more appropriately termed pseudanthia or inflorescences, since they’re actually multiple flowers in a single structure). Let’s look at them closer:

This macro shot shows a number of red bracts surrounding the flowers and extending out of the frame. The green balls tipped with red are individual inflorescences called cyanthia, which are composed of multiple flowers surrounded by modified leaves¹. The green tissue surrounding each inflorescence is an involucre, a cluster of bracts (modified leaves) fused into a cup-shaped structure that contains multiple male flowers and one female flower within it.

Emerging from each involucre are red filaments supporting yellow anthers that are being grown by the male flowers (the anthers produce and release pollen).  A single female flower should be emerging from the center of each involucre, but isn’t easily visible in the picture.

The yellow liquid-filled structures attached to each involucre are nectar glands filled with nectar to attract pollinators.  On less-developed inflorescences the nectar glands look like little light-green lips.

If you’re in the Orange County area and want your own poinsettias to observe the flowers of, head to OCC this Friday and pick some up for yourself!  You’ll get a cool botanical specimen, and will be supporting a great program in the process. Oh yeah, and you’ll have a nice pretty plant for the holiday season.

[This is the first in a series of three posts; the second post is: Poinsettia flower closeups take two: getting even closer and the third is Poinsettia flowers part three: the female parts.]

¹ Yes, the plant works hard to hide its flowers. First there are dozens of large colorful bracts, and then smaller green ones. Sheesh!

Getting There

Orange Coast College’s Ornamental Horticulture Department: OCC’s Horticulture Department is in a walled-off area on the west side of campus (see a campus map here). To access the gardens park in the Adams lot (off of Adams between Harbor and Fairview in Costa Mesa, CA) and head to the pathway between the new two-story Biology Building and Horticulture; along that pathway you’ll find a large gate that gives you access to their grounds. The gardens are free to enter anytime the gate is open.  Just inside the gate there’s a little lawn and a few classrooms. Walk behind the classroom building and continue heading north past their supply area (away from the Biology Building and towards Adams Ave.) and you’ll find the real gardens with large open lawns, trees, many tables to sit at, and even a pond at the back.

Parking in all OCC lots is by permit only during the week, though parking is free on the day of the poinsettia sale if you follow the signs to the sale in the Adams lot.  If you want to visit the gardens on another day you’ll need to find metered parking spaces; the closest metered spaces are in the Adams parking lot near the Chemistry building.

The gardens are closed on weekends and whenever classes are not in session.