>I need help with Dendrobium aphyllum [Is it the pink, super fragrant >flower commonly known as D *pieardii.* or agreen fimbiate lip or >another] and if there are differences between it - Dendrobium cuculattum >[is this the right name for the pink D *pieardii?]* and D. stuartii/ D >tetradon [comber says this is the green flower, fimbriate lip that turns >yellow with age. Comber separates D stuarti from D aphyllum and gives D >tetrodon as a synonym of D stuartii.
Hi Jay. You are blundering into an area where angels fear to tread. Firstly, you've missed out a name ... Dendrobium macrostachyum Lindley. According to Paul Ormerod, this 1830 name should be used instead of Dendrobium aphyllum (Roxb.) C.E.C.Fisch., which was first used by Roxburgh in 1795 as Limodorum aphyllum. I don't know the reason why Paul says the earlier name is incorrect. There seems to be some dispute amongst botanists about which name to use; most recent publications have used D. macrostachyum, but Howard Wood (2006) used D. aphyllum. Dendrobium pieradii Roxb ex Hook refers to the same species, but is an illegitimate name. The colour is quite variable. In different parts of the range, different colours predominate, so in Laos it is usually white with a white or cream lip, in Malaysia it is usually mauve with a cream or pale yellow lip, in Sulawesi it is pale yellow-green with a yellow-green, cream or off-white lip. In most specimens the veins on the lip are a different colour, usually either mauve, purple, pink or red. The lip is tubular, covered in small hairs, and usually has longer (often rather coarse) hairs near the margins at the apex. After that, things get more complicated. Everyone agrees that Dendrobium tetradon is normally peloric (flowers green or yellow) and self-pollinating, but there is dispute about what the "normal" form is. A popular candidate is Dendrobium stuartii, but not everyone accepts this. Other taxa, such as D. macrostachyum (D. aphyllum) have been suggested. Some authors state that D. tetrodon has no "normal" form & is a good species in it's own right. The whole situation is made even more messy by the uncertain status of D. stuartii. This name was proposed by Bailey for an Australian plant which is occasionally peloric and usually has self-pollinating non-peloric flowers that only open slightly. "D. stuartii" was subsequently applied to specimens from as far away as Thailand and Vietnam. Many of these Asian specimens are peloric, and look to my eye very much like the peloric D. tetrodon. If D. tetrodon is actually the same as the peloric forms of D. stuartii, then "D. stuartii" will take priority. Other Asian specimens of D. stuartii are slightly-opening, self-pollinating and non-peloric, ie much like the Australian Type. However, when critically analysed, these Asian non-peloric plants have a close resemblance to D. macrostachyum (ie D. aphyllum). So some authors lump the whole lot together. The Kew Orchidaceae website does this; it has an impressive list of synonyms under D. aphyllum. This approach has its advantages ... it is a very practical method of settling the issue. Others don't like it. They maintain that it is illogical to make connections between species based on peloric and other "abnormal" specimens and hence keep the names separate ... even though in this case, two of the taxa are "normally abnormal", if you know what I mean. Some botanists would split things up even further, and claim that the Asian specimens of D. stuartii aren't that species at all, and that the "normal" form of D. tetrodon is close to, but not the same as D. macrostachyum. The trouble is, there is no real evidence for any of this. One day someone will bung the whole lot into a blender and compare their DNA. Until then, one man's guess is probably as good as another's. If I was you I'd seriously consider adopting the Kew approach for your website, because it offers a solution to what will otherwise be a pretty intractable problem. Cheers, Peter O'Byrne _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
