Of Peloric Orchid Flowers and Form Names


Splash-petaled cattleyas owe their unique color patterns toCattleya intermedia ‘Aquini’, the abnormal three-lipped form of the species. Dendrobium nobile var. cooksonianum with three lips is another famous oddity. Phragmipedium lindenii with three normal petals and an extra stamen occurs as entire populations, but this is unusual among wild plants. Peloric flowers (called teratologies by older authors) have been documented for a very long time (e.g., Masters in Veitch,1894). Occasionally a collection plant produces a peloric flower under stress, and the peloria may exhibit any of many forms—doubled flowers with many tepals; an extra petal instead of a lip; three lips instead of petals; union of a petal with a sepal, etc.

Recently Joe Dixler from the Illinois Orchid Society requested identification of a plant with peloric flowers as a possibly undescribed form of Paphiopedilum philippinense. Recall that a form in botanese represents a particular genetically based oddity, and doesn’t refer to a plant population as the term variety does. Nor is the term useful to denote plants that revert to normal.

Joe sent the inflorescence, a leaf, and a flower in alcohol. The inflorescence displayed five flower seats. The bottom three open flowers had partially non-fused lateral sepals, two petals, no lip and normal stamens and staminode. However, the fourth barely opening bud was normal with the lateral sepals fused to near the apex, and it included a normal lip (the fifth bud was undeveloped). Is this a new and undescribed form? The question rests on whether the odd flowers are constant. The fourth flower demonstrates that it is probably not, and the best prediction is that the next flowering will be normal. Therefore, at this time there is no justification to give it a form name. End of story.

So, what is the cause of these odd flowerings? A few years ago contaminated Benlate was linked with peloric flowerings. Several years ago I purchased a Laelia purpurata from the Gardens plant shop that displayed no less than 13 flowers and buds including a lateral branch; unheard of in laelias and cattleyas. We attributed this to Benlate, although without proof. Subsequent years yielded no more than seven flowers per renewal shoot (growths). There were other reports of leaf variegation and malformation allegedly related to Benlate in other orchids. There are no doubt many causes. I have seen Cypripedium reginae and a hybrid (read “bulldog”) paph produce a petal with adjacent fertile stamen in lieu of lip as in the case of Phragmipedium lindenii, but the plants reverted to normal on subsequent flowers.

Joe explained that his plant had but a single healthy shoot which may lead to our answer. The anotopetalum paphs in general require at least portions of three renewal shoots: one, sometimes two mature shoots, plus a third developing shoot. His plant may have been subjected to trauma (drought? temperature extreme? excessive pesticide or fertilizer application?). In any case, the normal fourth bud is an indication that future flowerings should be normal.

From my extensive collection of 12 orchid clones, Paph. ´ St. Swithin featured in a previous Selby Vignette is now commencing flowering with one flower and five more buds. The first flower opened with three separate sepals and distorted staminode and passed before any remaining buds had opened. The sheath with promise of flowers appeared over a year ago, but development required a year, suggesting the possibility of distortion through interruption of development. Growing this plant as a house plant for eight months of the year is probably related to the delay. Whatever the cause, only plants that exhibit them regularly justify recognition as botanical forms.

 Literature Cited

Masters, Dr. Maxwell. 1894. Teratology of Orchids in Veitch, James & Sons, A Manual of Orchidaceous Plants 10:37-49.

 Figure. 1. Paphiopedilum philippinense plant. Photo: Joe Dixler

Figure 2. Paphiopedilum philippinense flower. Photo: Joe Dixler