scientific defining feature of orchidaceae?

[glengary54]

Bob - One of the things not mentioned is that all orchids have pollenia instead of pollen.

[Call_Me_Bob]

Thanks glengary! I'll be sure to include that!

[MadOrchidist]

Don't forget 3 petals and 3 sepals with bilateral symmetry.

Orchid flowers are bilaterally symmetrical, meaning they are only symmetrical along one axis (a line cutting through the flower yielding mirrored right and left halves). This distinguishes them from the closely related lilies, which are radially symmetric (you can draw three such lines through a lily and get symmetrical halves).

This is because, in orchids, one of the three petals has been modified into a lip (which has then secondarily been reduced in some things like Masdevalias).

[Ray]

Andy Braun gave a presentation on this act BCOS Thursday, stating 5 things that combined make an orchid an orchid:

1) Zygomorphy. Looking straight at a flower, it can only be cut in one plane - vertically down the middle of the dorsal sepal and lip - and still result in symmetry. Many other types of blossoms can retain symmetry when cut in a number of different planes.

2) Fusion of sexual organs into a single structure, as has been stated.

3) Waxy pollinia, rather than dusty pollen.

4) Lack of internal nutrient storage in the seed.

5) Modification of a petal into a lip.

[Call_Me_Bob]

thank you everyone!