Orchids, But Not As We know Them

Dr. Helen Millner

Helen is a lecturer in Plant Sciences at Wolverhampton University. She completed her Phd on reproduction and conservation of Restrepias. She doesn’t have a lot of time to grow orchids, but knows a lot about these cool growing South American species. She can often be seen at orchid shows with poster displays usually about orchids, but often other subjects as well. Working in research at a university gives good access to high powered cameras as well as large scale printing…

We all think that we know quite a bit about orchids as we see them on our windowsills, but when you see them in detailed close up they are different. The first image shown was some yellow spiky bits (fimbriations) that are often seen on the lips of many orchids. It resembled C. digbyana – but could be anything. The next showed more of hairy bits & warts, which was a close up of the petals on Paph. sukhakulii, which also has a hairy lip (pouch) and fine hairs on the staminode.

A lot of the close up images comes from her initial work on Restrepias. These are small flowers to start with, that need dissecting to photograph the column and reproductive parts. They have 4 pollinia that are held apart from the stigmatic surface by the rostellum. Only very small flies can access these parts to effect pollination.

Prosthechea cochleata is a plant we are familiar with as the octopus orchid. This is actually a species that flowers the right way up (non-resupinate) and as such makes it difficult for an insect to land on it to then access the pollen. They need to hover towards the anther cap to land, and then thread their way through what looks like a zip mechanism.

Bifrenaria species have long flowers without actually resorting to a spur. Insects need to delve to the bottom, and it uses a split lip to prevent both pollinia going onto the same insect – as well as preventing self pollination. Some of the rostellum are actually mobile to allow for tricks like this.

Den. (formerly Cadetia) taylori has interesting small white flowers that in close up reveal papillae on the lip that resemble hairs. This species has small arched petals that force insects towards the column, and others in these miniatures use antenna type guides

The South American rainforest is warm and wet, and this can often prevent insects landing on smooth lips – or even being washed off. Platystele sp. tend to have flowers of only 2mm wide. Within this they have a relatively large lip that is filled with papillae to enable the insects to keep hold.

Dryadella is a genus that grows in clumps with lots of tiny flowers within the leaves which are quite inconspicuous, but if you look at them through massive magnification they are quite colourful.

Many other pictures were shown of floral parts in great magnification that without the images are impossible to describe. An excellent lecture that we will remember for quite a while. One or two questions were asked, and answered, and a good round of applause followed. Many thanks, Helen.