Campylocentrum fasciola (Lindl.) Cogn. 1906 a Puerto Rican orchid "in situ" in the Rio Abajo forest

Few people notice these orchids, and even fewer have seen the flowers.  These orchids are not rare, they are just so inconspicuous as to be invisible.  The plant has no leaves, is it composed of a very short stem and roots that can be more than a forty centimenters long.  They prefer to grow on twigs.  The plant I observed only opened the first flower at the base of the inflorescence, all the others remained closed.  The flower is about one millimeter wide.

To bloom before dying, the precarious life of twig epiphytes

A Dendrophylax that is in a piece of bark the tree has shed sends a root toward the nearest branch

A Miconia tree trunk showing the bark that is about to be shed.

This Leochilus is kept in place by its numerous roots even though
the base of the plant is not attached to the tree

In trees that don't shed their bark the branches can become literally
 carpeted with all manner of epiphytic plants

Tillandsia seedlings in a twig of an orange tree. 

A Campylocentrum has found a favorable spot on a branch and is fruiting heavily.  The Ionopsis on the smaller branch will probably fall along with the dead branch in which it is growing.

Most people picture the life cycle of epiphytic orchids as one that is fairly sedate.  They have the impression that once an orchid germinates in a tree it can spend decades growing and blooming seasonally with little change to its circumstances.   This is true for many species, but not for all.   In particular, the life of orchids that prefer to grow in twigs is a race to bloom before the tree sheds the bark or the twig dies.

Why would an orchid grow under such precarious circumstances?  My own guess is that these orchids are exploiting a niche where they face little competition from other plants.    I have observed that the local orchids sometimes develop such extensive root systems that they alone can keep the plant attached to the tree when the twig or branch dies.  Also, they seem to bloom while quite small, no seven year wait to reach adult size and bloom with these orchids.  However even with all these adaptations life is precarious for these orchids, if one walks on the forest after a particularly windy storm it is common to find fallen twigs often with Ionopsis orchids on them.  In the forest around my house you can find Dendrophylax, Ionopsis, Campylocentrum and Leochilus in the branches of Miconia and Guava trees.

Campylocentrum filiforme, a bizzare native orchid that challenges our concept of what an orchid must be

Campylocentrum filiforme, the stems visible in the photo are new and old inflorescences and not the main plant body which is buried under the roots

The roots you see criss crossing the branch in the photo are the orchid, no leaves or stem is visible, inflorescences with seed pods are visible in the center of the photo

A close view

A close up shows the roots which look silvery white when they are dry but turn green when wet, both live and dead roots are visible in the photo

Campylocentrum filiforme ranks among the most bizarre of all of our native orchids.  What people universally regard to be the “orchid”, and I am referring here to the plant body, in this species has become reduced to an extreme degree.  The stem of this plant has been reduced to the point that it barely reaches a centimeter in length.  And the centimeter of stem that comprises the plant body is practically invisible due to the many roots that surround it.  In this species the roots dominate to such an extent that the plant is predominantly a tangle of roots with the stem forming a vanishingly small proportion of the biomass of the plant.

As a result this plant is the orchid world equivalent of a ghost.  Due to the apparent absence of a stem most people fail to recognize this plant as an orchid or even as a discrete plant.  Perhaps a particularly observant person might notice that there are orchid roots growing around the twigs and branches but since there are no leaves in sight anywhere it is probably that it will fail to perceive that the tangle of roots itself is the orchid.

This orchid is regarded as among the most advanced, from an evolutionary stand point, of all orchids.  The plant has abandoned the stem as a locus of photosynthesis and has shifted this function entirely to the roots.  What advantage can this radical departure from the norm of the plant world can this adaptation give this orchid?

The most accepted theory is that the leave less condition of the plant allows it to survive on the meagrest of resources, in a niche where no other plant can compete successfully or even survive.  These plants are mainly found in places where humidity is abundant such as swamps and moist forest areas but I have them also growing in disturbed areas.   Because they depart from most people conception of what a plant must be they are utterly invisible to the average person.  Because they survive with such limited resources these plants are not known to produce large or showy flowers but there are a few exceptions.

 Dendrophylax lindenii, the Florida Ghost orchid, another leave less species of orchid, made news all over the world when a plant in a reserve produced nine flowers at the same time, an unusual event.  The plant itself could hardly be distinguished in the photos from the bark of the tree where it was growing so, on first sight, the inflorescences with their large showy flowers looked like they were springing from the trunk of the tree.

Campylocentrum filiforme is classified as a rare orchid by Ackermann in his book on orchids of Puerto Rico and the Virgin Islands.  But it may be that it is more abundant that records indicate given its stealthy nature.  Apparently nothing is known about the pollination of this species.  It is not in cultivation and probably almost all local orchid growers are unaware that these plants exist.  I have never seen then on exhibition even in shows where there have been displays specifically devoted to native orchids.  Seems to be short lived in the wild as all the plants I monitored died when the twigs in which they were growing decayed.