ORCHIDACEAE  Juss., Gen. Pl.:
64, 1789 (nom. cons.); Adanson, Fam. Des Plantes 2: 68, July – Aug. 1763.

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. 

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Wikipedia link

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FAMILY OF THE WEEK: ORCHIDACEAE – indiantreepix | Google Groups

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Botany Hawaii link 

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Orchidaceae, Uttarakhand, Western Himalaya, India. – Check List

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Status, threats and conservation strategies for orchids of western Himalaya, India

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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.

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Present Status of Orchid Species Diversity Resources and Distribution in Dibrugarh District of Assam of North East India: 

I am sending you one of my recently published paper which is published online. Please give me a comments on it.

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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.

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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.
Picture books are of no use if you wish to learn….

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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 !!!

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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:
Apostasioideae
Vanilloideae
Cypripedioideae
Orchidoideae
Epidendroideae

Keys for subfamilies (Barretto et al. 2011: Orchids of Hong Kong)

1. Stamens 2 or 3 … 2
    Stamen solitary … 3

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

 … EPIDENDROIDEAE

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?

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This is a nice and very controversial question.
It is actually not very certain how many orchids are there in wild, infact i am sure that even for Asteraceae the diversity in not know. All are speculation. Yes Asteraceae is assumed to be the largest family and Orchid could be second largest. I have some reference where orchid diversity is estimated to be 36000 but I also have other
references which shows a figure of around 26,000. Actually I believe none of the two figures are exact for either of the family, but I do hope Asteraceae should have greater species than Orchids. Please also
remember that the number of non-naturally growing orchids (hybrids) are estimated to be around 150,000.
Secondly the rate of new species described in Orchidaceae seems to be higher than from Orchidaceae, but yes, my information are biased towards Orchids.
Its like asking a Nikon fan which camera is best and they say Nikon and if you ask a Canon lover they say Canon.
So dont worry sir, number is not so important. 

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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
mycorrhiza are of two types, one which are very generalized, i.e., they can infect seeds from many species; second which are very specific, as they can infect very specific seeds. These fungal filaments or mycorrhiza links seeds with another plant and kind of helps in transfer of food from other plant (live or dead) to the
orchid seeds. One more fact is, there could be more than one mycorrhiza associated with the seeds in one time.

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.
So if there is a specific fungi which can infect orchid seed and is found in a SAL forests, then this also implies that the orchid will be found exclusively in the SAL forests and nowhere else. If the orchid and fungi have very generalized requirement then they tend to be very widespread.

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.
Please feel free to question back if you don’t understand any point. 🙂 

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That’s like the best teacher.. simple and lucid language 

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.
People say that epiphytic orchids are not found at higher elevations.
But this is not true. Some taxa like Dendrobium brevicaule are found upto 4000m elevation. Overall, terrestrial orchids reach much higher elevation that epiphytic ones.

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
area, they either adapt well or they die. In rare cases they try to customize themselves to the new environment giving rise to a new species over a long period of time. Orchids are cross pollinated and natural hybrids are known to occur in wild. Cross pollination helps in maintaining high genetic diversity within and between different populations.

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..i will like to know more about SUB-TERRENEAN orchids how they can grow below ground

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.

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Very interesting indeed…thanks, don’t you have pics of any Aa species? is this name still valid??

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I got the answer of my second question after googling, name is valid…first question stands..

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No sir, I dont have any pics taken by me, there are some on google.

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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.
Some orchids have modified structures looking like pollinators to attract pollinators with an illusion to mate, OPHYRS, CALYPSO
Some orchids are structured in a way to shelter insects and while living in the flower, insects pollinate, SERAPIAS
Some orchid traps insects for pollinators, CORYSANTHES, PAPHIOPEDILUM
Some orchid emits smell of decaying flesh and flies come to lay eggs, DRACULA, BULBOPHYLLUM

These are just very few examples. I assume the types of pollination found in orchids are more than the total types of pollination found in any other group of plants.

Thanks a lot … should this be “Ombrophily”? very interesting… A paper

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Physical and Chemical mimicry in Orchids!

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Oh sorry Ombrophily 🙂

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Yes this can be called as Physical and Chemical mimicry and deception in Orchids 🙂

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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?

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No ants are not in preference but I was trying to think of pollinators in my head in alphabetical order.
Yes there is an orchid genus called Dracula and even there is a species called Dracula vampira.

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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.

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These are interesting questions.
1. GENETIC COMPATIBILITY: The basic need is to understand how hybrids are formed. In Orchids there are upto 3-generic hybrids. It all depends upon the genetic compatibility. But hybrids can be of three types; one which form fruits with viable seeds and other that form fruits fruits without viable seeds and third one which doesnt form fruit, although they all flower. There are unsuccessful hybrids which never flower and hence rejected. Orchids family is big with around 26000 species but there are only very few of the genera which are used
to making hybrids such as, Vanda, Ascocentrum, Rhynchostylis, Aerides, Phalaenopsis, Cattleya, Laelia etc. Most of Phalaenopsis are crosses with only Phalaenopsis giving vivid colours. Orchids have greater
chromosome number which also a reason for being able to cross. But hybridization is a long and tedious work and it really takes lot of experience and TIME to get one successful hybrid. Infact there are orchids that are self incompatible, that is, they never make fruits when fertilized with pollinia from same mother. Now a days they also use protoplast fusion. That is they just fuse the protoplast of two species together and WAIT AND WATCH.
2. VELAMENOUS ROOTS – Orchids always have velamen in their root system which is capable of absorbing moisture and nutrients from atmosphere.
3. SEEDS OR BY VEGETATIVE PROPAGATION OR BY SEEDLINGS: If you are making an hybrid then obviously you need to cross, get the seeds and germinate the seeds to get seedlings. These are all done in hitech labs or even in a normal lab. The best way is to get a healthy plants, identify the mycorrhiza associated with the roots. Culture the mycorhiza and do the crossing. Once seeds are formed they can be given the same mycorhiza medium mixed with the soil or even within the culture to help in growth of the seedlings.
4. Hybrids also have good fragrance, but not always.  Depends on what trend u want to see in a hybrid. Lets see you have white Phalaenopsis and a very mediocre flowered Phalaenopsis which has good fragrance. It
depends on hit and trial method keeping in mind how you will get the fragrance gene transferred to the white flowered one. So you make crosses and wait and watch. If you know the gene causing the fragrance
in flower then that gene can be isolated and transferred to the other plant.

Hope this helps

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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.  

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ORCHIDACEAE Fortnight: Preformation of flowers/ inflorescence/ aerial shoot in alpine orchids :  

Attachments (1). 10 posts by 9 authors/

Old literatures in Orchidaceae : 2 posts by 1 author. Attachments (1)- Pollination in Encyclia.pdf- 3 MB