Why are they different genera if they can interbreed?

[BearWithMe]

Sorry if this is a dumb question of if asked before - I didn't know what terms to use to search for this topic.

I was thinking that different species can interbreed, and that is what makes a hybrid. But I thought that different genera could not interbreed. Even then, some species can interbreed but the result can't breed, like mules.

Obviously, there are thousands of intergeneric hybrids for orchids. Are the terms used differently for orchids, compared to other plants or animals? Or I just don't know what I'm talking about? That last is a good possibility too.

[kiwiorchids]

Just put it this way: Orchids ignore every single rule that other plants adhere to.

Apart from the MRS C GREN rules, those apply to every living thing.

[Germinatorman]

Here is just a shallow level of the division of orchids. You can dig much deeper into Families and Sub-Families, Tribes, Sub-Tribes, etc.....

■Kingdom Plantae
■Phylum Magnoliophyta
■Class Liliopsida
■Order Orchidales
■Family Orchidaceae
Family Orchidaceae or the Orchid Family or Orchidaceae is further subdivided into several subfamilies. Each subfamily is further divided into smaller tribes that are further divided into sub-tribes. The orchid sub-tribes are further grouped under different alliances and respective genera. Though orchid taxonomy continues to engage some debate, contemporary studies agree that there are five main subfamilies along with 22 orchid tribes, 70 sub-tribes and 850 genera. It is important to have a basic knowledge about the five main orchid subfamilies as these are often mentioned when differentiating different orchid types.

1. Subfamily Apostasioideae
■They are the most primitive form of orchids
■Characterized by the presence of two-to-three fertile anthers
2. Subfamily Cypripedioideae
■They are monophyletic, i.e. presence of two fertile anthers
■Identifying feature — a shield-shaped stamen with a pouch-shaped lip
■Consist of nearly 115 types of terrestrial orchids
3. Subfamily Orchidoideae
They have a single, fertile anther that stands erect. The Subfamily Spiranthoideae is ususally included as a part of Orchidoideae.

4. Subfamily Epidendroideae
■The single anthers are identified due to their sub-erect structure, i.e. they tend to grow towards the outer edges
■Most widespread subfamily represent more than 80% of the orchid species, i.e. more 10,000 types of orchids
■Subfamily Higher Epidendroideae are now considered a part of Epidendroideae and not a separate entity
The most common species of orchids found in gardens around the world include Phalaenopsis, Dendrobium and Oncidium. All of them belong to this subfamily. Phalaenopsis or the Moth Orchid is known to bloom around the year. Dendrobium is popular for having the biggest leaves among orchids. The Oncidium or the Dancing Lady is a popular ornamental orchid that has a brilliant sprouting of flowers.

5. Subfamily Vanilloideae
■A prehistoric and controversial subfamily
■Earlier regarded as a part of both, Epidendroideae and Orchidoideae

[Kmac]

Don--thanks forposting that. I've seen it before. but this time I am going to print it out. Since you seem far more up on this than am i, can you tell me why some orchids are in "tribes" and some in alliances"?

[Germinatorman]

My own take on that is tribe is assigned by those that know and alliances are assigned by those that love orchids. In other words, I believe the scientific community uses tribe and sub-tribe as parts of the diagram that defines an individual organism. I am thinking that alliance is more of a grouping not used by that group, more by the layman.

[PaphMadMan]

Sorry if this is a dumb question of if asked before - I didn't know what terms to use to search for this topic.

I was thinking that different species can interbreed, and that is what makes a hybrid. But I thought that different genera could not interbreed. Even then, some species can interbreed but the result can't breed, like mules.

Obviously, there are thousands of intergeneric hybrids for orchids. Are the terms used differently for orchids, compared to other plants or animals? Or I just don't know what I'm talking about? That last is a good possibility too.

There are no set criteria for defining and distinguishng genera - it is based on whatever physical criteria someone thinks are useful and important at the time - usually long before they could have any idea if the organisms they are looking at could interbreed. It is not that the terms are used differently in orchids, just that orchids happen to retain the ability to interbreed with related types despite very large physical differences. As long as all the plants placed together in a genus are more closely related to each other than they are to any species outside the genus it isn't wrong, just a matter of convenience and interpretation. Once a classification is made it is retained unless someone takes the time to make a more compelling arguement.

[Germinatorman]

And then there is the ongoing between the Splitters and the Lumpers - with or without DNA!

[Kmac]

Interesting thread, thanks for all the info!

[BearWithMe]

Thanks for the comments!

There are no set criteria for defining and distinguishng genera

I guess that is why I've been confused. I thought it was genetic!

[Brutal_Dreamer]

Thanks for the comments!

There are no set criteria for defining and distinguishng genera

I guess that is why I've been confused. I thought it was genetic!

I know, right?! Very confusing sometimes.

cheers,
BD