Two Beauties

Pleurothallis (syn. Acronia) cyanea

Two of our loveliest Pleurothallids have been flowering simultaneously on the same tree in the Tropical High Elevation House. They make quite a show together.

Pleurothallis (Acronia) calceolaris

Pleurothallis (Acronia) cyanea and P. calceolaris are allied species. Notice how similar the flowers are, apart from their color. Both have a deeply concave synsepal (in the 6 o'clock position), like a broad oval bowl. The lateral petals of the two species are similar in shape, narrowly triangular.

Now compare the dorsal sepals (in the 12 o'clock position) of the two species. The blood red flowers of P. calceolaris have a dorsal sepal that is tall and appears narrow because the margins are reflexed backwards. I like the pebbly (verrucose) texture.

P. cyanea has a dorsal sepal broadly oval in shape and wrinkled in texture. It has a lovely shimmering quality in the sunshine.

P. cyanea and P. calceolaris are both native to Colombia. We grow our plants as epiphytes on trees in the Tropical High Elevation House. We choose a shady location on the moist interior branches of a tree. When we attach an epiphytic orchid to a branch, we use a minimum amount of moss over the roots in order to encourage them to establish directly on the branch rather than in the moss. The downside of using less moss is that the plants need more frequent watering. But that's a small price to pay for increased longevity.

A Mystery Orchid

This stopped me in my tracks. Flowering for the first time near the top a tree in the Tropical High Elevation House was an orchid I'd not noticed before. With its big solitary flower, it looked almost like an adolescent Pleurothallis gargantua. But the feeling that something was amiss sent me scurrying to the back up greenhouse for a ladder and then a closer look.

The handwritten label from Ecuagenera Nursery read 'Pleurothallis teaugei + gargantua.'  Odd. What did the plus sign mean? If Ecuagenera had created a hybrid, wouldn't they have labeled it with the names of the parents, separated by an 'x'? Is this plant a hybrid? Are teaguei and gargantua the parents?

Here's Pleurothallis gargantua, with its enormous solitary flower. For a quick guide to the floral parts, go here. The sepals look very much like those of our unknown orchid. But note that gargantua's rosy petals and yellow lip are very different.

And here's Pleurothallis teaguei flowering in the Tropical High Elevation House. If our unknown orchid is a hybrid, it could have inherited the rolled white petals from a teaguei. But where is it getting its rosy lip? Most likely not from gargantua or teaguei.

Flowering simultaneously was Pleurothallis marthae. With its rolled white petals and rosy lip, it appears to be a more likely contributor to the unknown orchid's genome.

But I can't be sure. The first step toward putting a name on this plant is to email a picture to Ecuagenera Nursery and ask for their data. Pleurothallid hybridization isn't exactly trending among commercial orchid growers, but I wouldn't be shocked if it were a hybrid. The larger Pleurothallids are fairly easy to pollinate. Alternatively, could this be a plant that Ecuagenera collected not in flower, and perhaps the names on the label were meant to be speculative? Could it be a species? There is nothing like it in Icones Pleurothallidinarum.

Whatever it is, our mystery Pleurothallis is a handsome plant. You can see it flowering now on the tree next to the door to the Conservation greenhouse.

The Frogs

The frogs are flowering. The "frogs" are a group of related orchid species within the vast subtribe Pleurothallidinae. (Acronia section Macrophyllae-Fasciculatae or Pleurothallis subsections Acroniae and Macrophyllae-Fasciculatae, depending on who you ask). The hooded sepals and spongy lip give the flowers the whimsical appearance of open-mouthed frogs. They are awesome.
  
What's inside those gaping mouths? Frog flowers can be baffling if you approach them with the expectation of seeing the conventional 3 + 3 arrangement of orchid petals and sepals. Here is a close up guide to a couple of the larger species, Pleurothallis gargantua and Pleurothallis marthae.

The dorsal sepal is usually erect and often concave. The lateral sepals are fused to form a synsepal. Lying opposite each other like the two halves of a clamshell, the dorsal sepal and synsepal give the flowers their mouth-like appearance. Pleurothallis gargantua (above) is a spectacular example and the largest of the frog Pleurothallids.

Pleurothallis marthae produces flowers that seem to remain half open. In the photo above, I've pulled back the dorsal sepal so you can see the interior of the flower from above. The column is short and the stigmatic surface is at its apex, not on the underside. The tiny anther has a detachable anther cap covering a minute pair of teardrop shaped pollinia.

Above, I've cut away part of the leaf of Pleurothallis marthae so you can get a closer look at the inflorescence. The inflorescence emerges near the apex of the ramicaul, a secondary stem that looks very much like a petiole. (The actual petiole is quite short and is separated from the ramicaul by an abscission layer.) The inflorescence is subtended by a sheath, called a spathe, that mostly obscures the peduncles. From the peduncles the solitary pedicels arise, each surrounded by a clear tubular bract, and emerge from the spathe. Among frog Pleurothallids, flowers are produced singly and one at a time (as in Pleurothallis gargantua), or singly and simultaneously (as in P. marthae).

The 'frogs' in the Tropical  High Elevation House are putting on an amazing show right now. Don't miss these terrific orchids!

Openings: Pleurothallis cyanea

There are some real stunners for you to see in the Fuqua Orchid Center right now. And they aren't even part of the Orchid Daze display. Like this plant, my own personal heartthrob, Pleurothallis cyanea. It is part of our permanent collection.

What is it about this plant? Maybe it's the subtle blue-grey (cyanea means blue) tint of the leaves. Or their elongated heart shape. Or the geometry of those arching veins. It achieves perfection, even when it's not in flower.

Oh yeah, the flowers. They seem to emerge, unexpectedly, near the top of the leaf. (Actually, they emerge where the stem meets the leaf, at the angle formed by the two rounded basal lobes.) The lower half (actually, two sepals, fused) of the 'clamshell' is concave, and rosy pink. They are elegant in their simplicity.

Pleurothallis cyanea is native to Colombia, where it grows as an epiphyte in wet tropical forests. Our plants are mounted on trees in the Tropical High Elevation House, placed where they receive lots of shade.

For some reason, just about all of our large-flowered Clamshell Orchids (Pleurothallis subg. Pleurothallis section macrophyllae-fasciculatae): Pleurothallis cyanea, P. marthae, P. gargantua, P. teaguei and P. titan are all flowering simultaneously. Now is a great time to see this terrific group.

Clamshell Orchids & Friends

Enough pretty (at least for the moment). How about something quirky? The orchid family is, after all, huge. Would we really want everyone in our family to be a beauty contestant?  

Pleurothallis teaguei somehow manages to be simultaneously quirky and wonderful. It has heart shaped leaves the size of salad plates, with flowers bursting from (what appears to be) the center, like some weird bouquet. And like many of the Clamshell Orchids (Pleurothallis section macrophyllae-fasciculatae), it produces a bouquet every time a new growth matures, which can be several times per year.

The warm growing Pleurothallids are easy to grow here in Atlanta. They're at the low light, high moisture/high humidity end of the cultural spectrum. Once established, they hate root disturbance. Uproot an established plant, and you can expect to wait years for forgiveness.

We've planted a number of the larger Pleurothallids around the Tropical High Elevation House. Though they are epiphytic, they are also perfectly content planted in a conservatory bed in a well drained mixture of fir bark, charcoal and permatill. They grow equally well in pots in a mixture of long fibered premium sphagnum and chopped tree fern, or as epiphytes mounted on larger trees.

Openings: Week of April 30

Cyrtochilum serratum in the Tropical High Elevation House

Whenever one of our ravishing cyrtochilums flowers I want to call the newspaper. They are just so exceptional in every way--exceptionally beautiful, exceptionally rare in cultivation, and unfortunately, exceptionally difficult to grow outside of the cloud forest. I feel flattered when one of ours flowers.

All of the Cyrtochilum species are native to the misty upland forests of the Andes where their extraordinarily long rhizomes scramble up trees and shrubs. But it's the flower spike, or inflorescence, that will make you stop for a second look. It's a graceful twining strand that winds its way up, around and among surrounding trees like rainforest tinsel, with as many as 100 flowers per strand.  Cyrtochilum serratum is  native to Ecuador and Colombia. If you guessed that Cyrtochilum is closely related to Oncidium, the Dancing Lady Orchid, you are correct.

Medinilla magnifica

Magnifica indeed. Without a doubt, the most commented upon plant in the Orchid Center right now is Medinilla magnifica, one of the all time great plants for conservatories. Not an orchid. It is a large shrub in the mostly tropical and frequently ornamental Melastomataceae. I have noticed M. magnifica for sale in Atlanta garden centers this month. It is not hardy in Atlanta. Melastomes, even large ones like Medinilla magnifica, are easily rooted by cuttings.
We have quite a nice collection of melastomes at ABG, and if you like M. magnifica you will love our recently installed Medinilla miniata, similar in size and aspect, but with fiery red flowers. Melastomes come in all sizes, but they are easy to recognize. The leaves are opposite with veins that lie parallel to one another. The flowers have a peculiar feature: the stamens are elbow-shaped.

Pleurothallis cyanea on a tree in the High Elevation House

If you visit the Tropical High Elevation House this week you will see a burst of flowers on some of my favorite clamshell orchids, Pleurothallis cyanea, P. gigantea and P. teaguei,  P. marthae and ever-blooming P. titan. I love the thick coriaceous leaves on Pleurothallis cyanea.

Cavendishia grandifolia

Cavendishia grandifolia is one of the most impressive plants in the Tropical High Elevation House and certainly our largest shrub. It's astonishing to realize that this plant, with its fifteen foot pendant branches is an epiphyte. It's a mighty plant that can support one of these sprawling monsters. Each of the thick platter-like leaves is ten to twelve inches long. You can get a closer look at those gorgeous tubular flowers here. We have two grandifolias: the one pictured above cascades over the waterfall; the other is draped over the arch of the tepui.

Lots of orchids in flower this week! Please stop by for a visit.

Openings, Week of December 12

Pleurothallis gargantua in closeup. The flowers measure 1" across by 3" long.

Now is a great time to catch an amazing flush of flowers on the Pleurothallids in the Tropical High Elevation House.

Pleurothallis gargantua planted in the ground in the Tropical High Elevation House. 

Pleurothallis marthae can be grown as an epiphyte or as a terrestrial.

A yet-to-be-identified Pleurothallis growing epiphytically on a cedar tree

All of the Pleurothallids pictured above belong to my favorite section of the genus Pleurothallis, the Macrophyllae-fasciculatae, colloquially known as the clamshell Pleurothallids.

Not all Stelis are micro miniatures. This species produces flowers 1/2" diameter--huge for a Stelis.

I love it when the Pleurothallids steal the show!