ORCHIDACEAE Juss., Gen. Pl.:
Orchidaceae Juss. forms one of the largest family of flowering plants on earth with over 26000 species. Some even say the number of species is above 35000.
They have varied range of habits, habitats, morphology etc.
Can be identified on the basis of labellum which is a modified petal, gynostemium and pollinia, which are modified forms of reproductive organ, where androecium and gynoecium are fused together to form single structure. Roots are covered with velamen tissue to provide moisture and nutrients.
The family is further classified into 5 sub-families:
Apostasioideae: 2 genera and 16 species, south-western Asia
Cypripedioideae: 5 genera and 130 species, from the temperate regions of the world, as well as tropical America and tropical Asia
Vanilloideae: 15 genera and 180 species, humid tropical and subtropical regions, eastern North America
Epidendroideae: more than 500 genera and more or less 20,000 species, cosmopolitan
Orchidoideae: 208 genera and 3,630 species, cosmopolitan
This is interesting to note that all sub-families are represented in India with a species richness of above 1300 species (1341). At the same time new species are being discovered and described every year.
newly published paper- A checklist of orchids in Tinsukia District of Assam, India: I am sending all of you one of my newly published paper for your comment. I received the PDF copy today.
I am sending you one of my recently published paper which is published online. Please give me a comments on it.
Orchid publications : 3 posts by 3 authors.
I would be thankful to those who may share any detail of publications on Indian orchids. Though I have orchids of WG & flora of Himalayas but need one for the country oriented publication.
Flora of Birtish India by J.D.Hooker should be enough for you and it will help you learn Orchid taxonomy too. Then to have information on updated taxonomy you can use The Plant List or Kew Checklist of Monocotyledons.
Orchidaceae Juss.: The House of ERRORS : 2 posts by 2 authors.
Orchidaceae the name of family starts with an error as this name described by Jussieu in 1789 has been conserved against Orchidaceae described by Adanson that was described earlier in 1763.
Another error is the Type of family which is Orchis latifolia L. but it is a rejected name now.
The name itself is originated from Orchis meaning TESTICLES !!! I imagine what was in the mind of Linneaus when he named Orchis !!!
Orchidaceae Juss. Fortnight: Classification : 7 posts by 6 authors.
Orchidaceae family is the biggest among the flowering plants comprising of nearly 36,000 species spread across the world from hot tropics to the arctics. They can be identified by their unique third petal which is modified in extraordinary structures to attract pollinations; androecium and gynoecium which is fused to form a gynostemium; anther which is modified to form waxy or powdery pollinia apart from velamnous roots.
Family Orchidaceae is grouped into 5 subfamilies namely:
Keys for subfamilies (Barretto et al. 2011: Orchids of Hong Kong)
1. Stamens 2 or 3 … 2
2. Flowers actinomorphic or sub-regular; lateral sepals free; lip petal-like, sometimes broader; column fused only at the base of the filaments; anthers 2 or 3, erect above lip; stigma terminal … APOSTASIOIDEAE
Flowers zygomorphic; lateral sepals usually fused almost to the apex; lip usually deeply saccate or
urn-shaped; column with 2 lateral anthers and a terminal, sheild shaped staminode; stigma
ventral, stalked … CYPRIPEDIOIDEAE
3. Plant usually terrestrial, growing from tubers or a horizontal fleshy rhizome; pollinia segmented,
comprised of massulae, or mealy … ORCHIDOIDEAE
Plants usually epiphytic or lithophytic, ocassionally terrestrial or liana-like, usually growing from cylindrical stems or pseudobulbs borne on woody or tough rhizomes; pollinia mealy or hard, often attached by a stalk to a sticky viscidium … 4
4. Plants vinous (or terrestrial); stem cylindrical, never with pseudobulbs; pollinia 2 powdery, arranged in monads or tetrads, lacking stipes and distinct viscidium … VANILLOIDEAE
Plant epiphytic, lithophytic or ocassionally terrestrial; stems cylindrical and/or with pseudobulbs; pollinia 2, 4, 6, 8, usually hard, rarely sectile, often attached by 1 or 2 stipes to 1 or 2 distinct viscidia
Good introduction of Orchidaceae with keys to subfamilies …
I have a humble query here about the diversity of the family. While teaching Orchidaceae to students I always mention that it is second largest family in the world (after Asteraceae) with 925 genera/ 27135 species as per The Plant List 2010. The other sources also mention number of genera and species as 880/22075 (APweb), 750-800/20000=25000 (Takhtajan 2009) etc. As I saw the number mentioned by you (36000spp) I felt it essential to correct my data. Please mention the source so that I may update my notes. Is this number for naturally occurring species?
This is a nice and very controversial question.
ORCHIDACEAE Juss. Fortnight: Orchid and Mycorrhiza, the two best friends !! : 7 posts by 6 authors.
Orchids have lightest seed among the angiosperms and one of the reason for that is the lack of endosperm, that is the, reserved food material. So orchid seeds need external support to germinate. Here comes the role of mycorrhiza, a kind of fungi.
Fungi in turn are always very specific as we know that there are very specific fungi that infects specific fruits. This compatibility depends on the ability of the fungi to infect another organism, the composition of the cell wall of both. In case of orchids, first infection is when fungi gets associated with the seed. Such fungi or
Now where this fungi is found is also very specific, a fungi growing in warmer temperature will not be found in cooler areas; a fungi growing in very high humidity will not be found in drier areas; and one of the most specific thing is, a fungi that is found in the litter of SAL tree leaves, may not be found on the TEAK tree leaves.
To meet up with all this fungal requirement, one orchid fruit holds millions of seeds, but yes the chance of survival is very low, but even if it is 5 % that’s enough for every year.
Fungi also acts as a kind of biological control otherwise with so many species and so many seeds, there would have been orchids growing in every corner of the world!!!
NOTE: I am trying to use very simple and not technical words, so as to make it understandable to every one.
That’s like the best teacher.. simple and lucid language
Thanks for this info 🙂
Thank you … for this wonderful information in simple words. This mycorrhiza is specific and this is the reason that we can not grow orchids through seeds easily. A big lacuna is the case of Dactylorhiza hatagirea which is exploited from wild but can not be cultivated as we do not know the fungus exactly.
I think there are works on mycorrhiza of Dactylorhiza outside India.
ORCHIDACEAE Juss.: Habit and Habitat : 13 posts by 8 authors.
Orchids are very unique and they are found in wide range of habitats at diverse elevations.
Still they are highly sensitive. They can be EPIPHYTIC (growing on other trees- not as parasite); TERRESTRIAL (growing on ground); AQUATIC (growing in water); SEMI-AQUATIC (growing near water or in areas which are waterlogged for significant duration of the year); SUB-TERRENEAN (growing completely below ground).
They occupy great range of elevations depending on the region of earth they are found.
Orchids occupy wide range of habitats. However the diversity is lower in homogenous vegetation where as it is higher in heterogenous forests. Highest diversity is found in warm and humid areas like tropical rain forests.
One of the main reasons for their high diversity and wide distribution is the absence of endosperm in the seeds. Hence they are very light and can be carried to greater distance by wind. When they fall in new
..i will like to know more about SUB-TERRENEAN orchids how they can grow below ground
also examples and pictures ( if possible )
Its doesnt matter a lot how plants grow just on the ground surface (I didnt say underground, I said Sub-terrenean). The roots and stem are underground. It is almost leafless, some leaf like structures are
Orchids are lithophytic too. eg. Luisia, Pholidota, Coelogyne though the same species may be found as epiphytic over trees.
Yes sir, Orchids are lithophytes too, I missed it, but I include them into epiphytes.
ORCHIDACEAE Juss. Fortnight: Shortest plant name – Aa : 10 posts by 6 authors.
Heinrich Gustav Reichenbach (Dresden, 3 January 1823 – Hamburg, 6 May 1889) was a botanist and the foremost German orchidologist of the 19th century. His father Heinrich Gottlieb Ludwig Reichenbach (author of
Icones Florae Germanicae et Helveticae) was also a well-known botanist.
He had this very strange desire that when ever a plant dictionary is made, the plant name on the top should belong to him. To fulfill his desires, he named an orchid genus as “Aa”.
This genus is represented by around 35 species distributed from Central America to Northwest Argentina.
Very interesting indeed…thanks, don’t you have pics of any Aa species? is this name still valid??
I got the answer of my second question after googling, name is valid…first question stands..
No sir, I dont have any pics taken by me, there are some on google.
ORCHIDACEAE Juss.: Pollination Ecology : 14 posts by 8 authors.
One of the main reasons why orchids have highly modified flowers is due to a basic fact that they are meant to be cross pollinated. They need to attract pollinators and for this they put in much more effort than just modification of flower parts. Attracting pollinators can be done by two basic ways: producing rewards for visitors or proding faking rewards for pollinators. Rewards such as NECTAR, WAX, RESIN etc, Those orchids which cant produce these try to lure by producing fake products, like something that looks like resin but its not resin.
Orchids can be pollinated by, ANTS, APHIDS, BEES, CRICKETS, RATS, BIRDS, WASPS, HORNET, RAIN, AIR, BUTTERFLY, MOTHS etc.
Some orchids emit fragrance similar to pheromones of the insects to attract those particular insects, Ophyrs, Bulbophyllum, etc.
Thanks for detailed information.. really a great diversity of pollinators they have.. I have heard Rain pollination for the first time, should this be called Hydrophily?
Thanks a lot … should this be “Ombrophily”? very interesting… A paper
Physical and Chemical mimicry in Orchids!
Oh sorry Ombrophily 🙂
Yes this can be called as Physical and Chemical mimicry and deception in Orchids 🙂
Thank you … for the detailed information. I am surprised to hear a genus called dracula. Where do you find this ? Did you mean that ants are the main pollinators in orchids by the preferance in sentence?
No ants are not in preference but I was trying to think of pollinators in my head in alphabetical order.
Orchidaceae Fortnight::General Questions : 8 posts by 4 authors.
The Orchidaceae fortnight is going in full swing with an overwhelming response from all members, I have some doubts about Orchids being from non-botanical background.
1) Why most of the hybrid varieties in plants are found from Orchids and roses and not from other families?
2) Being an epiphyte how these plants prepare food just with air and moisture? Even if the tree supporting the plants is dry the orchid plant survives.
3) As for germination of a single orchid naturally, requires millions of seeds and presence of some fungi, how the wild varieties are cultivated in gardens?
4) Most of the naturally occurring orchids have a very good fragrance as well as colours, but the hybrid ones have no fragrance but come in vivid colours – an observation.
Experts are requested to throw some light on these doubts.
These are interesting questions.
Hope this helps
2) Orchid roots are especially adapted to absorb and conserve water and survive dry spells. This is because of many-layered epidermis which soaks water like a sponge. The roots are also equipped to collect a lot of debris (nest epiphytes) from which the roots are able to absorb water as well as nutrients available through decomposition of debris. As far as manufacturing food is concerned, they do it like any other green plant through their leaves.
3) Wild plants especially those which are perennials (orchids or others) are mostly collected from wild, bunches split and planted in appropriate soil for propagation and maintenance under cultivation.
In Orchids very often Velamen makes fungal associations to derive nutrients from atmosphere and also from the host tree or just barks.
Velamen also helps in anchoring to the host surface.
Thanks a lot … the valuable information.
Please remember all that collecting wild orchids and planting them in your garden is technically illegal in India and its 100% restricted if the plants are inside protected areas
Added to Orchidaceae Fortnight page- efi thread
Attachments (1). 10 posts by 9 authors/
Alpine zones in the Himalaya have short growing season lasting for 6-7 months only and rest of the time these areas remain covered with snow. In such a short growing season plants have to grow, produce flower, compete for pollinators, set seeds and disperse them to complete their life cycle. Many of the plants including alpine orchids (Dactylorhiza hatagirea, Goodyera fusca, Malaxis muscifera, Malaxis cylindrostachya etc) form flower/ Inflorescence or entire aerial parts of plant body in miniature form inside their perennation (overwintering) bud. It is an advance preparation for early and rapid growth in next season. Since all the parts are preformed rapid growth is possible after snow melt. But what could be the source of energy for such rapid growth? In D.hatagirea each year a new hand shaped tuber is formed underground which is full of stored food (carbohydrates) earned in current years photosynthesis, while stored food of last year’s tuber is used up for rapid growth. So each year one new tuber is formed while older tuber is exhausted. Both of these tubers can be seen at the end of season (September-October), one turgid- full of stored food, while other shrunk and decaying devoid of stored food. Attached picture tells the story.
Thank you all for liking this information. There are many other alpine plants which show this strategy of preformation. More details are in enclosed article.
Old literatures in Orchidaceae : 2 posts by 1 author. Attachments (1)- Pollination in Encyclia.pdf- 3 MB
I have attached two scanned old articles on Encyclia and Catasetum species from Costa Rica. I hope this would be useful for some.