Aerides odorata Lour. 1790 is the type specimen for the genus
Aerides. As the name implies fragrant flowers, I find some of them are odorless. The species is widespread through the Himalayas, mainland, penninsula, and islands of Southeast Asia. Because of its widespread habitat, variation in color and form is noticable in plants from different geography. Unfortunately, the orchid is too common here in Songkhla and I did not take a picture of its flower. This photograph is from
http://www.orchidfoto.com/displayimage.php?album=170&pos=1.
I notice a variation in flowering period in different habitat as well. Different flowering time may cause separation of the species in the far future as the genetic diversity accumulates among their own subgroups. Native
Aer. odorata in Songkhla blooms in May to June, the usual season for many
Aerides spp. in Thailand. However, the plants I bought and cultivate in my greenhouse in Songkhla just bloom in August to September. The plants were documented by the vender to be from the south of Thailand but I don't know the exact location they were from. They have yellow lips while the native plants in Songkla have white lip with light pink tip. I put the plants near
Aerides lawrenciae Rchb. f. 1883, the native
Aerides to the Philippines with larger flowers and similar lip shape. It is quite amazing the the two species bloom at the same time.
Usually,
Aer. odorata flowers last for only one week while those of
Aer. lawrenciae last longer than two weeks. So I am observing how long the flowers of these yellow-lip
Aer. odorata would last. Cross breeding between the two species is not a good idea since they are too much alike and we cannot expect any new phenotypes.
Do not think of butterflies to pollinate such orchid flowers with tough structures like this. Usually bees can do it. However, common bees are too small and light so that they cannot open the flower lip to get inside and pollinate the flowers of
Aer. odorata. For many years, I wonder what is the mechanism this orchid used to pollinate and maintain the existence of its species since the lip completely covers the column and anther cap. I discovered a few years ago when I collected data on health system in a health center in the south of Thailand. There were some
Aer. odorata blooming on the tree trunk near the health center and the flowers attracted large capenter bees which were heavy enough to open the lip. They could pollinate the flowers when they searched for nectar inside the spur covered by the closed lip and got out with pollenaria on their head. They tried again on other flowers and the pollenaria was traped in the rostellum filled with glue-like sticky fluid. This pollination mechanism of
Aer. odorata was scientifically reported by Chaturved & Chaturved in the International Journal of Plant Reproductive Biology 2(1) pp. 45-49, 2010.
There are no capenter bees around my university. Thus fortunately enough, I accidentally found another pollination mechanism myself in front of the Administrative Building of the Faculty of Medicine, Prince of Songkla University in the south of Thailand. When the orchid bloomed, yellow beetles (
Lema pectoralis Baly, 1865) came to fed on their flowers and laid their eggs. During the unfortunate sacrifice, some flowers (in fact a lot of them) were pollinated. A few days later, the capsules grew with sepals and petals eaten. Good sacrification isn't it? Unfortunately I didn't take the picture of this pollination mechanism. I borrow a picture of yellow beetles on Aer. odorata flowers from http://goodmotherearth.blogspot.com/2011/06/leaf-beetles-or-love-bugs.html. Another picture shows a flower (not an orchid) eaten by the beetles. http://www.flickr.com/photos/sarawaklens/3715778349/.
It grows well at low altitude at sea level and in hot and humid weather of the southern Thailand. It is a rare species without any attractive feature, thus, no hybrid has been produced from this species. 
