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!

Paphiopedilum wardii

Paphiopedilum wardii

Paphiopedilum wardii is a gorgeous olive green Asian Slipper Orchid native to Myanmar and southern China. I have always admired its coloration. But what's the story with the glistening bumps above the flower's pouch?

Several species of slipper orchids in the genera Paphiopedilum and Phragmipedium are visited by female hoverflies (Syrphidae). Female hoverflies select aphid colonies as brood sites for egg laying and their larvae eventually devour the aphids. John Atwood has observed hoverflies laying eggs on Paphiopedilum rothschildianum's staminode, which has raised glandular hairs. He concluded that the glandular hairs appear to the hoverflies to resemble the bodies of aphids. Atwood also observed the female hoverflies pollinating the orchid. This phenomenon--the attraction of female insects to false egg-laying sites in flowers --is called brood deception pollination.

Recently, Robert Pemberton has made several observations of hoverflies picking up pollina from Phragmipedium pearcei. Calaway Dodson also noted pollination of Phragmipedium longifolium by a hoverfly. Like most species of Phragmipedium, these two species have spots above the lip. It seems likely that the spots on Phragmipedium flowers attract hoverflies and facilitate brood deception pollination.

Is Paphiopedilum wardii pollinated by hoverflies? Is it pollinated through brood site deception? I don't know, but those glistening bumps would seem to suggest so.