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.

Anguloa clowesii

Anguloa clowesii flowering at the Atlanta Botanical Garden

I love that some of our Tulip Orchids are flowering indoors while our Horticulture staff is planting actual tulips outdoors.

Tulip Orchids are Andean in origin. Anguloa clowesii is native to Colombia and Venezuela where it grows at 1800 to 2800 m on the western slopes of the Andes. It was collected in 1842 by Jean Linden near the Nevado of Tolima, a Colombian volcano. Alvaro Arango M. writes in Orchids of Colombia, Vol. I, that in order to throw other collectors off the trail Linden reported it to be from the Sierra Nevado of Santa Marta, a coastal mountain range much farther north and not a part of the Andean mountain chain. This sort of deception was a fairly common practice among competing collectors. Linden named his discovery after one of the British financiers of his expedition, the Rev. J. C. Clowes of Manchester. Linden and his son later founded one of the most profitable 19th century orchid collecting firms.

Tulip Orchid Tuesday

Anguloa hohenlohii

All of the Tulip Orchids are lovely, but the russet colored Anguloa hohenlohii is especially beautiful. The inside of the flower is gold overlaid with red spots.

Anguloa clowesii

If you can tear your eyes away from the flowers you will see the new shoot visible behind the flowers. Those new shoots are practically begging for food. Tulip Orchids can become very large in bright light, coolish temperatures and with regular fertilizing during active growth. Some of the largest that I have seen were grown by Marc Hachadourian at the New York Botanical Garden-- beautiful plants with enormous pseudobulbs and leaves nearly two feet tall.

Many anguloas produce new shoots and flowers simultaneously, a trait that can exasperate a grower. (Shoots produced after flowering is a more common sequence in orchids.) By the time our plants have finished flowering and returned to the back up greenhouse the young shoots are nearly mature. I have to rush like crazy in order to repot them all before they finish their annual growth cycle. And I already have plenty to repot!

Baby Boom in the Orchid Nursery

Orchid seedlings in one of our back up greenhouses

A big priority for us this year has been to pollinate some of the choicest orchids in our collection. We have two goals. The first is to generate more plants for installation in the Fuqua Orchid Center. The second, and more important, is to reinvigorate our collection by producing healthy young seedlings.

Sarah removes the anther cap from Anguloa clowesii

Selfing, or fertilizing a plant with its own pollen, is simple and can produce a reasonable percentage of vigorous orchid seedlings. But many rare orchids in collections today are highly inbred, the result of many generations of selfings. Some are the descendants of just a single plant collected in the wild decades ago, before CITIES restricted importation. Unfortunately, an inbred plant often grows poorly, a tendency that becomes more pronounced with age.

Removing the pollinarium from the anther cap

Any plant that is maintained in a collection for many years needs to be vegetatively propagated by cuttings or division at intervals in order to provide replacement material. But when inbreeding contributes to its decline, then performing an outcross (i.e., use genetically different parents to produce seed) can be the best way to obtain healthy offspring while preserving some of the original genes. Outcrossing introduces new genes into the next generation and means that more offspring will be vigorous.

Sarah pollinating Anguloa clowesii

Data-the date and parentage- is recorded on a label and on a form and then transferred to an Excel file

The label is attached to the orchid below the  ovary

In upcoming posts we will follow the development of some of our pods.