The Genus Bulbophyllum includes plants with a very wide range of growth and flowering habits. One of the more unusual is Bulbophyllum clandestinum and when we first saw this plant in the wild in Laos it took us a while to be sure it was an orchid species. It grows along a long pendulous rhizome and appears to produse thick alternate leaves along this rhizome like many non orchid climbing epiphytes. The clue to it being an orchid when not in flower are the tiny pseudobulbs at the base of each leaf and the distinct orchid roots that wind their way along the rhizome. Fortunately in Laos we found evidence of flowers too and although these are small they clearly belong to an orchid.
This Bulbophyllum is found across South East Asia and Malaysia and produces tiny yellow flowers along its rhizome between the pseudobulbs.
In Laos the plants were growing in low light at 1000m altitude and so we grow the plant mounted but hanging low and shaded in our Warm Asia section. Why not add an orchid with an unusual growth habit to your collection this year?
Regular followers of 365 days of orchids will have noticed an improvement in photograph quality since we started in January 2017. The team in charge of photography includes Joe, Ben, Ed, Otto and Ed and they have developed their skills over the past 13 months. Most photographs are taken with digital SLR or Bridge cameras although phones and i-pads with macro and microscope lenses are often used for very small flowers.
As you can see in the photo Joe is using a tripod and our black cloth photo area to take the picture for todays post – Pleurothallis truncata.
Small flowers can have a really big impact and this is certainly the case with Pleurothallis trucata. Each spring plants produce chains of remarkable little globular flowers on top of leaves and for about eight weeks there is a real show in Cool Americas.
The species is endemic to Ecuador where it grows from 1700m-3000m altutide in cool wet forest. We find the species thrives mounted, in pots and in baskets but if allowed to become too dry produced lots of little plants on the leaves (keikis) rather than flowers.
The species has the delightful habit of flowering when really small (under 10cm high) but over time becomes quite large and the plant shown here is 40cm across. The photograph below shows Amalia who is in charge of Pleurothallis in our own cloud forest – Cool Americas – with one of her Pleurothallis truncata plants.
Paphiopedilum species are dramatic and beautiful orchids but unfortunately they are being driven to extinction by a range of threats. In common with most Paphiopedilum species P. appletonianum is a terrestrial and grows in leaf litter and amongst boulders in warm forests from 300-1200m. According to its IUCN Red List Entry it has been found across South East Asia and in Southern China but has been stripped from many its former sites and ‘the population trend is decreasing due to many threats including ruthless collection for regional and international trade, exploitation for horticultural purposes, logging, habitat degradation and human disturbance.‘
The species like other members of the genus are easy to raise from seed in-vitro and wild collection is unjustified. However we have seen hundreds of illegal wild Paphiopedilum plants for sale in Laos and India. These illegal plants do find their way into Europe and so it is really important that people only but seed raised plants, and support conservation initiatives for the plants they love.
We have had our seed raised plants since 1998 and love this species’ leaves as much as its flowers. It enjoys deep shade in our Warm Asia section where we keep it watered throughout the year.
The pouch of Paphiopedilum orchids acts as a temporary trap for pollinating insects that can only escape by pushing their way past the stigmatic surface and then the sticky pollen so pollinating the second flower they visit.
One mystery with this species is the very long flower stem. Perhaps its pollinating insect never flies near the ground!
Dendrobium densiflorum has won the popular vote for Orchid of the Year 2017 – thanks to all of you that voted.
In honour of its victory I have reproduced an article written about the species in 2013 by student Zoe Barnes (then in year 11) that formed part of her group’s entry into the National Science and Engineering competition which they Won. Zoe is currently studying a degree in Environmental Science at Plymouth University and with her new commercial diving certificate is about to embark on Kelp research which she has promised to share on this website.
I am Zoe Barnes, a 16 year old student at Writhlington School. I am involved in the Writhlington Orchid Project where I am in charge of the Orchid Propagation Laboratory.
This project has been running for twenty two years and I have been part of it for the last five. During this time I have had the opportunity to go to South Africa, Rwanda and the Sikkim Himalayas. I am writing this article to focus on the most recent of my trips, the Sikkim Himalayas and more specifically, the orchid species Dendrobium densiflorum. Dendrobium densiflorum grows in several countries in the Himalayas; Bhutan,Nepal and some Northern states of India, which are; West Bengal, Assam, Arunachal Pradesh and Sikkim. It is found mostly as an epiphyte, although, occasionally it can be found as a lithophyte. It grows in the sub-tropical zone between 800 – 1600m above sea level and the flowering time for this species is between April-June. (1)
Fig.1 shows me holding a Dendrobium densiflorum in cultivation, in the collection at Writhlington School, and fig.2, is a close up of its flower. It has a beautiful deep yelloworange colour with the lip being darker than the petals and sepals. The name ‘densiflorum’ comes from the Latin densus and flos, meaning ‘dense flower’ (1), which is due to the way the flowers grow so close together. This is also, along with the colour, the reason for its common name; the Pineapple Orchid. (1)
Fig.3 shows one of the plants of Dendrobium densiflorum that I discovered in flower while in Sikkim. I found this at 1000m above sea level on a steep wooded slope. This photo is taken from the road side and that impressive epiphyte can be found close to main roads in Sikkim. There is no moss on the tree around the plant but it is growing quite close to other epiphytic orchids including other Dendrobiums, Eria species and Bulbophylums. I observed it was growing on the side of the thick branches of tall trees, with the roots spreading along the branches. The forest was open evergreen woodland alowing plenty of light to reach the Orchids. I travelled to Sikkim in April, which is at the beginning of the flowering time for Dendrobium densiflorum. This is why in the picture above there are some flowers fully out and others still in bud. This orchid has a faint and subtle smell. I couldn’t decide on my own what it smelt of, however after asking a selection of staff at Writhlington school the most common suggestions are; melon, honey and daffodils. People said it was a sweet smell and reminded them of spring time.
The Writhlington Orchid Project has visited this part of Sikkim before fig.4 is a plant in a similar area to where I found them. As you can see the flowers are fully open as it was about two weeks later in the year. It was found in the same open evergreen forest and it is growing on the thick initial branches of a tall tree, similar to the ones that I discovered. To grow Dendrobium densiflorum successfully at Writhlington we try to replicate Sikkim’s seasonal climate and provide a warm wet summer (minimum 18°) and a cooler dryer winter (minimum 12°). We grow plants both mounted on bark and planted in baskets giving good drainage. We water heavily from May through to September but water plants infrequently during the rest of the year. Dendrobium densiflorum is an amazing orchid to research and to see in the wild. Its shape is memorable and links well to its common name, which also helps it stick in your mind. Once you have seen Dendrobium densiflorum in the wild, you will never forget its dense spray of stunning flowers glowing out through the green of the forest.
(1) ‘100 Sikkim Himalayan Orchids’ by Mohan Pradhan