Now opening: Coryanthes macrantha

We've produced a bumper crop of Coryanthes seedlings that are now reaching flowering size. Coryanthes, with their provocative morphology and intense fragrances are simply the best teaching tool ever for introducing students (or anyone!) to orchid pollination concepts, and Euglossine bee pollination in particular. But, since the flowers only last about three days, a large number of plants are needed for a continuous display.

We are very fortunate to have a mircro prop lab to allow us to produce orchid seedlings. Coryanthes are somewhat weedy in the sense that they reproduce rapidly. They have a very short capsule maturation (60 days), produce copious quantities of seed and robust, fast growing, fast flowering seedlings.

After they outgrow the plug stage, our Coryanthes seedlings grow best on vertical mount, rather than in a pot or basket. Tree fern slabs have worked well for us, but last year, in an attempt to wean ourselves from our tree fern dependency, we tried a new slab material: coarse filter media, borrowed from our aquarium colleagues.

Filter media isn't a good choice for every orchid, but the Coryanthes love it. Within a couple of months, their roots completely fill the interior spaces of the slab.

We are super excited to have more of these fascinating orchids on display for you to see. Look for them this year in the Orchid Display House!

Coryanthes macrantha buds

The Fuqua Orchid Center is a garden of surprises. I walked into the greenhouse early yesterday morning and came face to face with the pinched and furrowed face of a Coryanthes macrantha (Bucket Orchid) bud. The light was dim and I think I jumped.

For sheer bud awesomeness, nothing beats Coryanthes.  A Coryanthes labors for weeks to produce two enormous buds. Those buds become the most riveting objects in the entire greenhouse. What's inside? 

Coryanthes macrantha

You can see Coryanthes macrantha on display this week in the Fuqua Orchid Center's Orchid Display House.

Openings: Coryanthes macrantha seedlings

Of course it's loads of fun to receive an orchid in flower. But even more fun is the exquisite anticipation that builds as you await the very first flowering of a newly matured plant. Will it resemble its parents? Will it be a surprising new color or shape? Or something intermediate? Do you ever envy plant breeders who experience this excitement for a living? Think about it. Many of them wait years to see their photosynthetic offspring's first flowers.

Flowering for the first time this month in our warm greenhouse are some seedlings of a fairly rare light colored form of Coryanthes macrantha, one of the Bucket Orchids.

Usually only a small percentage of the seedling offspring of an atypical form will resemble their parents. So I was expecting flowers with the typical bold red splashes. Surprise! Our first seedling has bred true. The petals and sepals are nearly white.

Of all the species of Coryanthes, Coryanthes macrantha is the most widely distributed. And throughout its range it exhibits some very striking color variation. Dr. Günter Gerlach's Coryanthes page on the Munich Botanical Garden's website has an outstanding catalog of Coryanthes descriptions and photos if you want to go crazy looking at the diversity in this remarkable genus. Dr. Gerlach notes that while the color and morphology of Coryanthes macrantha seedlings may vary throughout their range, the fragrances of all the clones that he examined are very similar. Coryanthes macrantha is pollinated by fragrance collecting Euglossine bees of the genus Eulaema.

More Coryanthes in Flower

Coryanthes macrantha flowering at the Atlanta Botanical Garden

More of our extraordinary bucket orchids are flowering. Coryanthes macrantha (above) is one of the parents of the hybrid featured in my last post. You can see what the other parent looks like here. Although Coryanthes are, in my experience, among the more difficult orchids to grow, Coryanthes macrantha has always been a consistently strong grower for us.

I'm also looking forward to seeing the first flowers on the seedling offspring of Coryanthes macrantha var. alba this year.

Coryanthes, the Bucket Orchid

Coryanthes macrantha flowering at the Atlanta Botanical Garden. The genus Coryanthes is called the Bucket Orchid.

How it works. The  Coryanthes "bucket" (facing right) is part of the flower's lip, a highly modified petal. The other two petals and three sepals (left) are reflexed backwards like wings. Coryanthes flowers produce fragrance attractive to male Euglossine bees. After brushing the fragrance from the lip, the bee falls into the bucket.

The back door. After immersion in the liquid-filled bucket a bee must force his way out through a small opening at the rear where a pollen bundle is deposited on his back. 

Autumn brings a flush of new root and shoot growth to our (insert your own adjective) Bucket Orchids. A few, like Coryanthes macrantha, are far enough along in their development to produce flowers. The flower pictured above measures about four inches from top to bottom. A Coryanthes flower would make anyone stop for a second look.