Orchids which have lost the ability to perform photosynthesis...

Didymoplexiella haianensis. by Jin Xiaohua. This is a new species of this genus described the photographer from Haianen,  China.

WORK IN PROGRESS

Most orchids photosynthesize, that is they are capable of making sugars and starches by converting sunlight into chemical energy. Rhizanthella slaterii , which is an Australian species (see below), is a terrestrial orchid which spends most of its life underground, coming up to bloom and be pollinated (R. gardneri by fungus gnats) and has completely become achlorophyllous. This is generally a rare thing in angiosperms, but among orchids, the loss of chlorophyll has occurred numerous times across the whole of the family; among the most primitive members of the epidendroid subfamily, it has occurred at least 5 times. The loss of chlorophyll is an interesting physiological change, but also results in interesting morphological and anatomical convergences such as reduced floral morphology and loss of leaves. If you look at the flowers of many of these plants, you notice a few key things. Firstly, they are all brown or white, with fused flower parts. Of course they lack any of the showy parts that attract insects such as  an extravagant labellum or intricate pollination mechanism (eg. Ophrys). The loss of chlorophyll, and hence holoparsitism (yes orchids are parasites), is a trait is found primarily among terrestrial orchids, although the loss of leaves are also seen in some Epiphytes such as the ghost orchids (Dendrophylax lindenii, above left); this species is however photosynthetic, but uses its roots, which have chlorophyll in them, to do the work rather than leaves.





Rhizanthella slaterii







This page is dedicated to wondrous orchids which are often ignored elsewhere because they are not too showy. Considered by some to be the ugly stepsister of the more showy vandoid and other orchids which are more common in cultivation. Even when they are showier, they are not easy to cultivate as they require fungi for their nutrients. These fungi are often unknown, and in some case are fungi associated with other green plants through which they get nutrients; you can imagine it might get a little crowded in the greenhouse with all of these associated plants and fungi around too. This aside, one should never underestimate beauty in any orchid let alone these. On this page you will find photos and general information on these plants.  I hope that you will be able to appreciate these plants a little more once you have been introduced .


             Gastrodia procera  in habitat. Taken in Australia

 

Corallorhiza wisteriana. The spring coral root orchid. Found in Ohio, it is considered rare and is considered an endangered or threatened species.

Cephalanthera austiniae or Phantom Orchid is a very rare orchid, found in western North America. This is the only species in the genus that is lacking chlorophyll, although there are mutants reported for other species which show this condition too. Photos by: © Mike Parsons. for more info see Dr. B. Klinkenberg at http://www.geog.ubc.ca/~brian/phantomorchid.htm

Epipogium roseum by Masahide of Japan

page by Erik Rothacker

rothacker.1@osu.edu