Bulbophyllum arfakianum

Bulbophyllum arfakianum unfurled its flowers for the first time last week, and I was felled on the instant. There isn't a single vantage point from which the flower doesn't look ravishing. Bulbophyllum arfakianum is native to West Papua, Indonesia. The specific epithet, arfakianum, references the Arfak Mountains, an outstandingly rich region of biological diversity on the Bird's Head Peninsula. Bulbophyllum arfakianum grows as an epiphyte in lowland forest at 50 to 400 meters elevation.

How many other flowers can you think of that look as fantastic from the back as the front?
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Pink Tulip Orchid

At first glance, it would be possible to mistake this beautiful plant for Anguloa uniflora, another pink tulip orchid species. But Anguloa virginalis is recognizable by its laterally flattened flowers with pointed petals and sepals.

Front view, showing how narrow the flower of A. virginalis is compared with  A. uniflora. Orchid flowers have bilateral symmetry. But like virtually all organisms, this individual defies any expectation of symmetrical perfection. The column is turned slightly left of center, reflecting a twist in the ovary and scape. The two lower sepals meet unevenly. One sepal points slightly leftward. I like these fascinating  irregularities.

From the side, you can see the distinctive kink near the base of the tubular lip -a feature that is diagnostic for virginalis.

Ventral view of the lip. From this angle, you can see that the kink in the lip is actually a depression in the ventral surface.

Dorsal view of the lip.

Anguloa virginalis is native to Colombia, Ecuador and Peru, where it grows as a terrestrial or lithophyte at around 2000 meters elevation in bright light. Henry Oakeley reports its habitat as full sun or light woodland and forest margins. Our plants like the cool temperatures (52º night minimum) of our Tropical High Elevation House where they are planted in the ground in a mixture of fine fir bark, charcoal and permatill.

A Natural Hybrid

It was the single orange flower in a sea of yellow tulip orchids that stopped me in my tracks. We don't have many Anguloa x ruckeri in our greenhouse and it was worth stopping for a second look. Anguloa x ruckeri is a naturally occurring hybrid between Anguloa hohenlohii and Anguloa clowesii.

It grows terrestrially at 900 to 2000 meters elevation in Venezuela and is known at least historically from Colombia as well, according to Henry Oakeley in Lycaste, Ida and Anguloa, The Essential Guide (2008).

This individual has inherited an overlay of red spots from its hohenlohii parent. They coalesce into a deep rose colored wash on the interior. After I removed a petal and sepal, the lip (on the left) became visible opposite the column.

The lip is joined to the column by a tiny hinge at the foot of the column. As is typical in anguloas, the column foot is very long -in the photo above it is deep red. The hinge allows the lip to swing toward the column, bumping the bee against the anther cap at the end of the column.

The upper surface of the lip. It is intermediate in shape between Anguloa clowesii and Anguloa hohenlohii.

The underside of the lip.

Oakeley states that Anguloa x ruckeri is reported as growing in the same conditions in the wild as A. clowesii and A. hohenlohii. In cultivation, our plants are growing well in an intermediate greenhouse with 60º night minimum temperature and 70% shade.

Winter Tulip Orchids

Here to rescue us from January drabness is an welcome burst of winter flowers on three of our Tulip Orchid (Anguloa) taxa: clowesii, virginalis and x ruckeri. It's not very often that we have three different taxa flowering simultaneously, so I thought this would be a good opportunity to take a closer look at each one. They are lovely.

Anguloas have large waxy fragrant flowers that attract male Euglossine bees. This particular Anguloa clowesii has a touch of wintergreen in its fragrance. The genus Anguloa is sometimes called the Cradle Orchid because the flower has a hinged lip. Let's open up a flower and see how that works.

The interior of the flower is easier to see after I remove one petal and one sepal.

The lip of an Anguloa is hinged. It is attached to the column foot by a narrow band that allows the lip to swing back and forth between the sepals and the column. I love plants with moveable parts.

According to N.A. van der Cingel in An Atlas of Orchid Pollination (2001), the male Euglossine bee lands on the lip, turns and backs into the flower. He holds onto the edges of the petals with his middle legs while scratching for fragrance with his front legs. On leaving, he releases its hold on the petals and his weight tips the lip against the column. The pollinarium is attached to his abdomen. I suppose bees are accustomed to holding onto moving surfaces and don't find this trapeze act unnerving.

The lip in dorsal view, a sturdy boat-shaped platform for the bee.

The underside of the lip.

Anguloa clowesii grows as an epiphyte or terrestrial at around 1600 meters elevation in Colombia and Venezuela. In cultivation they are often deciduous, although in our greenhouse they rarely lose all their leaves.

Next: Anguloa x ruckeri.

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.

Cycnoches warscewiczii, the Swan

Cycnoches warscewiczii ABG# 03-1121

Attention fans of Peristeria elata, the Dove Orchid. Allow me to introduce you to the Swan Orchid, which is flowering now in the Orchid Display House. Notice the graceful arching neck (the column), the white body (the lip) and chartreuse wings. Okay, it's an inverted swan, but never mind--it's lovely.

Cycnoches warscewiczii is just one of 30 or so species of Cycnoches, the Swan Orchids, which grow in the American tropics. Cycnoches produce flowers that are usually either male or female. In some species the male and female flowers look so strikingly different that they were initially thought to be different species.

The female flowers of Cycnoches warscewiczii

If you love orchid fragrances, you will want to experience this one. Like so many other Euglossine bee-pollinated orchids, this one smells delicious.

Acquiring pollen involves a sort of trapeze maneuver on the part of the bee. Even so, pollination isn't on his agenda at all. His goal is to simply to collect the liquid fragrance from the flower's lip, probably for pheromone production. As the bee grasps the margins of the lip with his two pairs of front legs, he releases his grasp with his two hind legs. His abdomen swings downward and touches the tip of the column, accidentally discharging the golden pollen masses onto his back.

The bee finishes collecting the fragrance and off he goes, cologned and resplendent, in search of yet more fragrance. Does he notice his cool new bling? Probably not. Eventually he arrives at a female flower, which he unwittingly pollinates while collecting fragrance.

Openings: Phalaenopsis celebensis

Phalaenopsis celebensis in the Fuqua Orchid Center

The silver mottled leaf of Phalaenopsis celebensis 

One of the sweetest Phalaenopsis species in our collection is this beauty: Phalaenopsis celebensis from the Celebes Islands (Sulawesi). Modest in size without actually being a miniature, Phalaenopsis celebensis has lovely silver mottled leaves that are pendant--droopy, actually, like hound ears.

The pristine white flowers, carried on a very long arching spike, are about one tenth the size of a hybrid Phal, but Phalaenopsis celebensis scores major points in my book for its charm. It may be my favorite Phalaenopsis species. Sarah pollinated our two plants yesterday, so we should be filling the nursery with seedlings before long.

Angraecum sesquipedale, The fragrant Star of Bethlehem Orchid

Angraecum sesquipedale flowering at the Fuqua Orchid Center

Angraecum sesquipedale

By far the most-asked question from nighttime visitors to the Orchid Display House is 'What smells so good in here?'

Winter is the season for night-fragrant Angraecoid orchids, two in particular. The first is Angraecum eburneum superbum, which starts flowering for us in November. The second is one of our most famous orchids, Angraecum sesquipedale, aka Darwin's Orchid, the Star of Bethlehem Orchid or the Comet Orchid, opening this week.

Angraecum sesquipedale is fascinating for lots of reasons, but today's post is just about its dreamy almost narcotic fragrance. The Darwin connection I'll take up in another post.

Angraecum sesquipedale is completely scentless during the day, and our daytime visitors just nod politely and walk away when told that it produces one of the best scents in the orchid family. But wait!

As darkness gathers the orchid releases a beguiling combination of scents--lily, Gardenia and Nicotiana. Interestingly, the scent changes as the flower matures. As Roman Kaiser writes in The Scent of Orchids, this description "applies to the fully developed flower on its 3rd or 4th night after blossoming. During the first two  nights, the scent is rather mixed, with a fairly marked indole note. This latter compound is found in the majority of night-scented flowers."

Night-fragrant flowers often produce scents reminiscent of jasmine, honeysuckle, tuberose, lilies and Gardenia. In the perfume trade, these scents are known as 'white-floral', and have been reproduced in a number of great perfumes.

Night-fragrant orchids that produce these scents are often white and are highly attractive to nocturnal moths and, apparently, people.

The effect on our nighttime visitors is remarkable. Many seem oblivious to the dazzling lights display as they veer off into the darkness in search of the source of the intoxicating scent.

More Mormodes

Mormodes oberlanderiana ABG# 05-1060 flowering at the Fuqua Orchid Center

A bee's eye view of the twisted column of Mormodes oberlanderiana. The shiny surface of the stigma is visible on the underside of the column.

From behind the flower you can see that the lip is twisted also.  The angle of  the lip and column creates  a characteristic placement of the pollinarium on the bee's thorax. When the bee enters a female flower the pollinia are in the correct position to be placed on the stigma.

The last of our four Mormodes species flowering this week is Mormodes oberlanderiana. I have to admit that I completely missed the subtle but gorgeous coloration of these flowers until I saw them in the morning light through my camera lens. What a beauty. Of the four species this one has, in my opinion, the most captivating fragrance.

Mormodes oberlanderiana is native to Colombia and northwest Venezuela where it grows as an epiphyte.

How to Grow Mormodes

Mormodes aromatica flowering in the Fuqua Orchid Center

Leopard spots on the flowers of Mormodes aromatica.

Mormodes are a blast to grow. It's enormously gratifying to pour on the fertilizer in spring and watch them explode. I love their indescribable fragrances and wacky pollination. Mormodes are rarely popular with the set who covet hybrid Cattleya flowers, or among folks who call small-flowered orchids "botanicals." It's their loss.

Want to grow Mormodes? Here's the key: They have an annual growth cycle that is strongly seasonal.

Mormodes are easy to grow if you pay attention to some obvious signals--yellowing leaves signal the onset of the dry season; new shoots signal the onset of the rainy season. Simple.

Here's how we grow ours:*

• Warm greenhouse (66º night min.) alongside Catasetum & Cycnoches.
• High humidity ~75% RH-- to keep thrips and mites at bay.
• Bright light. Ours grow adjacent to the Laelia bench.
• Plastic net baskets.
• A mixture of coarse fir bark, charcoal, perlite and premium sphagnum.
• Under our conditions they need water about every 3-4 days in summer.
• Twice weekly Cal Mag at 200 ppm supplemented with half-strength Nutricote.
• The dry rest lasts about two to three months, starting with leaf yellowing in October.
• By November & December they are completely leafless and in full dormant mode. During this time it takes about a week to ten days for the mix to achieve bone-dryness. Then we water. The advice to never water them during dormancy "because in nature they never receive rain during the dry season!" is misguided. Potted plant cultivation is not like nature. Two or three months in our greenhouse without supplemental moisture leaves the pseudobulbs badly shriveled.
• New shoots in spring are the signal to increase watering and repot.

*This isn't a recommendation for all Mormodes species grown under all conditions. Growing practices that work well in an Atlanta greenhouse need to be modified for conditions elsewhere.

You can find out about Mormodes buccinator and Mormodes sinuata by following the links.

Mormodes buccinator, The Bugler

Mormodes buccinator ABG #07-1033 flowering at the Fuqua Orchid Center.

The twisted column makes this orchid instantly recognizable as a Mormodes.

The ivory lip of Mormodes buccinator is not the broad landing platform that bees encounter on many flowers. The sides are rolled back and almost meet at their edges, giving the lip a trumpet-like shape--hence the name buccinator (Latin, bugler).

Mormodes buccinator grows as an epiphyte in lowland forests in Mexico, Guatemala, Honduras, Nicaragua, Venezuela, Colombia and Brazil at 450 to 1500 meters (1500 to 5,000 ft.) elevation.

This has been a good week for Mormodes in our warm greenhouse. We have four species in flower simultaneously. The blackened red Mormodes sinuata is featured in Thursday's post.

Mormodes sinuata, The Goblin

Mormodes sinuata. The yellow column is twisted to the side, exposing the anther.

Mormodes sinuata ABG # 07-2342 flowering at the Fuqua Orchid Center

'Like a goblin'--is the fanciful etymology of Mormodes Lindley (from the Greek mormo, meaning 'goblin'; and odes, meaning 'like a') describing this orchid's strange male flower with its twisted column. I can imagine how the features of a goblin's face might twist as it breaks into a grin.

Why would an orchid flower have a twisted column? Because it's part of a unique pollination mechanism. The twisted column places the pollinarium (the pollinia, stipe and sticky viscidium) in the correct position on the pollinator's thorax.

Charles Darwin was the first person to investigate how Mormodes flowers are pollinated when he studied Mormodes ignea (published in The Various Contrivances by Which British Orchids and Foreign Orchids are Fertilized, 1862).

The flower's fragrance attracts a male Euglossine bee (genus Euglossa). As the bee lands on the lip, it strikes the apex of the column, opening the anther cap. The pollinarium, with its sticky disc, swings forward onto the back of the bee. After 30 minutes the pollinia packet dries and uncoils into the correct position for placement onto the female flower.

Reading Contrivances again I have to admire Darwin's patient and painstaking attention to minute detail as he analyzes this whole procedure. "At the close of the twelfth trial I was in despair...," he laments. But he persists. With only twelve flowers at his disposal, Darwin figures out the mechanism using needles of different diameter in place of a pollinator.

Several more species of Mormodes have flowered this week. More pics will follow!